EARTH 

SCIENCES 

LIBRARY 


•  MAI\UA: 


OF 


GEOLOGY: 


DESIGNED  FOR  THE  USE  OF 


S, 

COLLEGES   AND   ACADEMIES 


BY 


EBENEZER  EMMONS, 
>» 

STATE  GEOLOGIST  OF  NOKTH  CAROLINA,  LATE  STATE  GEOLOGIST  OF  NEW 

YORK,  PROFESSOR  OF  NATURAL  HISTORY  AND  GEOLOGY 

IN  WILLIAMS  COLLEGE,  ETC.,  ETC. 


|ll«sfrateb  fcrifjj  numerous 


SECOND    EDITION 


NEW   YOEK: 
PUBLISHED   BY   A.  S.  BARNES   &   BURR, 

51   &  53  JOHN-STREET, 

AND    SOLD    BY  BOOKSELLERS    GENERALLY. 

1860. 


VI  PREFACE. 

ment  of  rocks  on  this  side  of  the  Atlantic  agree  with  those 
upon  the  other.  But  inasmuch  as  we  now  have  an  American 
geology,  let  it  be  taught.  It  is  for  our  interest  to  make 
foreign  geology  subservient  to  American.  But  we  need  not 
dwell  on  this  subject. 

One  of  the  most  important  studies  for  the  young  is  classi- 
fication. Its  advantages  are  not  confined  to  natural  history. 
In  every  sphere  of  knowledge  it  aids  the  mind  to  define  and 
limit  the  boundaries  of  subjects,  and  perceive  the  true  and 
constant  relations  they  hold  to  each  other. 

Our  opinion  of  its  utility  led  us  to  furnish  an  introduction 
to  the  subject,  which,  though  imperfect,  may  still,  as  we 
believe,  serve  as  a  basis  upon  which  classification  may  be 
taught. 

The  plan  we  have  followed  in  the  preparation  of  the  work 
differs  somewhat  from  others.  We  have  given  in  each 
chapter  treating  upon  the  systems  of  rocks,  a  general  history 
of  the  period  to  which  they  belong.  To  this  we  have  added 
a  brief  description  of  the  rocks  and  their  order  of  sequence. 
Each  system  is  illustrated  by  the  organisms  or  fossils  which 
it  is  known  to  contain,  and  which  have  been  generally 
selected  from  those  which  are  the  most  common.  The  geo- 
graphical distribution  of  American  formations  completes  the 
history  of  the  several  systems. 

Our  illustrations  of  characteristic  fossils  may  be  regarded 
by  some  persons  as  out  of  proportion  to  the  statement  of 
facts  and  principles ;  but  it  should  be  recollected  that  Palce- 
ontology  has  become  the  leading  branch ;  and  from  which  we 
derive  the  most  important  information  respecting  the  natural 
history  of  the  earth. 

This  feature  of  the  work  gives  the  general  reader,  as  well 
as  the  student,  an  opportunity  to  form  a  correct  idea  of  the 
progress  of  life  upon  the  globe ;  and  will  enable  him  to  con- 
trast the  palaeozoic  with  the  cainozoic  age,  from  which  he 
will  perceive  the  high  standing  of  the  organisms  of  the  latter, 
when  compared  with  the  former. 

Geology  is  comparatively  a  modern  science,  and  it  cannot 


PREFACE.  Vll 

be  supposed  that  its  doctrines  will  not  require  modification 
from  time  to  time.  Of  this  we  are  able  to  recall  many  in- 
stances. But  with  this  admission  we  feel  that  it  has  already 
established  a  body  of  well  settled  principles,  deduced  from 
well  determined  facts  and  observations.  These  principles 
constitute  a  sure  foundation,  upon  which  is  being  reared  a 
noble  superstructure.  Its  progress  has  been  in  no  respect 
different  from  other  sciences.  Chemistry  had  its  alchemistic 
age,  and  geology  its  cosmogonists,  but  this  fact  does  not 
diminish  its  importance,  nor  should  it  cast  doubts  upon  its 
conclusions. 

<  We  are  confident  we  are  safe  in  the  foregoing  opinions, 
notwithstanding  there  remains  a  slight  leaven  of  the  old  cos- 
mogonists. The  fact  is,  some  geologists  belong  naturally  to 
this  order  of  men,  and  geology  proper  would  be  too  tame 
and  spiritless,  if  it  were  not  that  some  of  the  crust  move- 
ments permit  them  to  be  converted  in  imagination  into  over- 
whelming convulsions. 

In  treating  those  subjects  which  required  a  place  in  this 
work  we  did  not  deem  it  necessary  to  discuss  them  to  ex- 
haustion. Much  may  have  been  said,  which  has  been 
omitted.  It  is  frequently  enough  to  bring  the  subject  up, 
and  leave  the  discussion  of  it  to  the  teacher. 

It  is  probable  that  our  own  views  upon  certain  geological 
points  may  differ  from  those  entertained  by  distinguished 
men.  Where  the  discrepancies  of  views  are  worthy  of  note, 
they  have  been  stated  and  maintained  in  this  work ;  because 
we  have  reason  to  believe  that  our  opportunities  for  forming 
a  correct  one  have  been  better  than  those  from  whom  we 
differ,  or  because  we  have  taken  special  pains  to  be  rightly 
informed  upon  the  subject,  and  hence  have  a  legitimate  right 
to  an  opinion. 

The  present  advanced  state  of  geology  demands  a  certain 
amount  of  information  in  the  collateral  sciences,  chemistry, 
botany,  and  mineralogy.  In  the  order  of  study  the  col- 
laterals stand  first.  To  become  an  accomplished  geologist 


Vlll  PREFACE. 

requires  a  considerable  amount  of  field  information  derived 
directly  from  observation.  Collections  should  always  be 
made  and  notes  taken  upon  the  spot,  detailing  all  the  im- 
portant phenomena  a  locality  may  furnish.  It  is  the  only 
mode  by  which  remunerating  results  can  be  obtained. 

KALBIQH,  May  1,  1859. 


TABLE  OF   CONTENTS. 


CHAPTER  I. 

PAGE 

Knowledge  and  its  departments — Characteristics  of  man  and  the  progress 
of  kingdoms 13 

CHAPTER  II. 
Classification 17 

CHAPTER  III. 
Classification  continued — Vegetable  and  mineral  kingdoms      ...          37 

CHAPTER  IV. 

Geology  defined — Its  objects,  advantages — Means  by  which  it  is  acquired, 
and  the  rules  by  which  its  phenomena  are  interpreted — Sources  of 
information  pointed  out — Importance  of  the  testimony  of  organic  re- 
mains— Geology  based  on  authentic  records — The  three  periods — Origin 
of  water,  and  continental  rivers  and  seas 42 

CHAPTER  V. 

Of  geologic  forces — Fire  and  water  considered  as  agents  of  change — 
Dynamics  and  statics  of  geology 46 

CHAPTER  VI. 
Classification  and  nomenclature  of  rocks  ......          51 

CHAPTER  VII. 

Classification  of  the  Pyro-crystalline  Rocks — Age  of  Granite  and  its  asso- 
ciates— Successive  formation  of  Granite  and  its  distribution — Individual 
rocks  described,  Ac 57 

CHAPTER  VIII. 

Second  System,  the  Laminated  Pyro-crystalline  Rocks,  Gneiss,  and  allied    . 
compounds— Third  System,  the  Pyro-plastic  Rocks,  Basalt,  Greenstone, 
Traps,  Porphyries,  &c.  .        .        . 64 

CHAPTER  IX. 

The  Pyro-plastio  Rocks 68 

(9) 


X  CONTENTS. 

CHAPTER  X. 

PAGE 

Of  the  Sediments  or  Hydro-plastic  Rocks — Agents  concerned  in  their  pro- 
duction— Recognisable  base — Progress  of  life  during  the  sedimentary 
periods — Amount  of  sediments — Geologic  time  .....  71 

CHAPTER  XL 

Taconic  System — Divided  into  Upper  and  Lower — Fossils  of  both  divi- 
sions .  ...........  81 

CHAPTER  XII. 

Silurian  System — General  statement  of  facts  relative  to  its  epoch — De- 
scription and  division  of  the  members  composing  the  system,  its  fossils, 
Ac ^.  90 

CHAPTER  XIII. 
Devonian  System 125 

CHAPTER  XIV. 

Carboniferous  System — An  important  epoch — A  stand-point  for  reckoning 
geologic  time,  vegetation,  coal,  and  prospective  material  designed  for  the 
use  of  man — Formation  illustrated — Vegetable  fossils — Division  of  the 
system  into  Lower  Carboniferous,  and  the  Coal  Measures,  &c. — Reca- 
pitulation   153 

CHAPTER  XV. 

Permian  System — Phenomena  marking  the  close  of  the  Palaeozoic  Divi- 
sion— Author  of  the  system,  and  derivation  of  its  name — Changes  in 
the  organic  remains — Permian  of  the  Atlantic  slope — Development  in 
North  Carolina — System  described  under  the  name  Chatham  Series, 
fossils,  Ac 172 

CHAPTER  XVI. 

Triassic  System — Divided  into  three  members — Base  of  the  Mesozoic  Divi- 
sion— Mineral  contents — Its  fauna  and  flora — Imprints  of  the  feet  of  birds 
and  batrachians 185 

CHAPTER  XVII. 

Jurassic  System — Imperfectly  represented  in  this  country — Its  position  on 
the  continent  of  Europe — Its  Saurian  remains — Character  of  the  sedi- 
ments— Divided  into  five  stages — The  Lias  has  three  groups — The  Wealden 
closes  the  epoch 198 

CHAPTER  XVIII. 

Cretaceous  System — Characteristics  of  the  Mesozoic  Division — Derivation 
•of  the  name  Cretaceous — Lower  Division — The  Green-sand  lithological 
characters — Fossils  of  the  Green-sand 203 

CHAPTER  XIX. 

Cainozoic  Division — General  characteristics  of  this  division — Sir  Charles 
LyelPs  subdivisions  of  the  Tertiary — Eocene,  Miocene,  and  Pliocene, 
&c.  .......  209 


CONTENTS.  XI 

CHAPTER  XX. 

PAGE 

Glacial  or  drift  period 246 

CHAPTER  XXL 

Post-glacial  beds — Alluvium — Eolian  Sands — Bottom  Prairie — Bluff  and 
River  Terraces — Coast  Sediments — Cavern  Deposits — Travertin — Coral 
reefs — Volcanic  productions 254 

CHAPTER  XXII. 
Volcanoes,  volcanic  action,  and  earthquakes 259 

CHAPTER  XXIII. 
Mineral  veins — Veins  of  rock  or  earthy  matter 264 

CHAPTER  XXIV. 

Mean  elevation  of  land — Ocean  level — Disturbances,  or  dislocations  of  the 
earth's  crust — Epoch  of  some  of  the  most  important  dislocations — Gradual 
and  paroxysmal  elevations — Relations  of  land  and  water — Changes  of 
temperature  induced  by  a  change  of  relations,  and  effect  on  the  distribu- 
tion of  plants — The  relations  of  igneous  rocks  to  disturbances  of  the  earth's 
crust * 267 

CHAPTER  XXV. 
Soils *  271 


MANUAL  OF  GEOLOGY. 


CHAPTER  I. 

KNOWLEDGE  AND  ITS  DEPARTMENTS. — CHARACTERISTICS  OF 
MAN  AND  THE  PROGRESS  OF   KINGDOMS. 

1.  The  sum  and  substance  of  all  knowledge  is  derived  from  the 
observation  of  Phenomena,  and  whatever  we  know  of  matter  or 
mind,  becomes  our  property  through  phenonema;    or,  what  may 
be  regarded  as  expressing  the  same  thing,  is  ours,  through  and  by 
associated  facts  of  which  we   become   conscious  by  our  mental 
operations. 

Knowledge  becomes  Science,  when  the  phenomena  of  existence 
are  so  far  known,  that  they  may  be  classified;  or  when  they  are  so 
far  known  to  us,  as  to  enable  us  to  express  ultimate  results  or  fixed 
relations.  • 

Mind,  is  that  which  thinks  and  wills  and  is  also  emotional; 
Matter,  is  that  which  is  known  to  us  through  the  medium  of  the 
senses;  and  hence,  knowledge  is  divided  into  two  great  depart- 
ments :  one  relates  to  Material  bodies,  and  the  other  to  Immaterial 
existences.  These  constitute  the  two  great  fields  of  human  research ; 
the  first  is  usually  called  Physical,  and  the  last  Metaphysical  science. 
Both  however,  are  prosecuted  through  and  by  the  intervention  of 
phenomena,  and  belong  equally  alike  to  existences  in  nature.  They 
include  together  the  facts  of  all  existences,  but  are  properly  sepa- 
rated as  their  fields  are  dissimilar  in  kind,  though  both  are  con- 
cerned with  phenomena  and  cannot  be  investigated  without  them. 

2 .  Physical  Science,  usually  called  Natural  Philosophy,  takes  in  its 
domain  all  the  phenomena  of  external  nature,  or  all  substance  which 

2  (13) 


14  MANUAL   OF   GEOLOGY. 

is  recognisable  by  our  senses.  But  its  domain  is  so  wide,  that  it 
becomes  necessary  to  subdivide  the  field  into  minor  areas,  each  of 
which  comprehends  distinct  and  separate  branches  of  science.  These 
have  received  appropriate  names,  which  have  been  applied  according 
to  the  nature  of  the  subject-matter  they  include. 

The  first  and  most  comprehensive  division  is  based  upon  the 
presence  or  absence  of  the  principle  we  call  Life.  This  leads  us  to 
form  two  great  divisions  of  matter,  one  of  which  is  called  Organic 
and  the  other  Inorganic  matter. 

3.  The  phenomena  of  organic  bodies  are  comprehended  under  the 
terms  Zoology  and  Botany.     They  are  also  called  Kingdoms.     The 
former  includes  in  its  domain,  the  associated  facts  which  relate  to 
Animals,  and  the  latter,  those  which  relate  to  Plants. 

4.  Inorganic  matter  includes  in  its  field  all  that  belongs  to  the 
earth  and  heavens,  not  included  in  the  former  divisions ;  it  there- 
fore comprehends  Astronomy,  Geology,  Mineralogy,  Chemistry,  &c., 
together  with  the  consideration  of  those  forces  which  belong  to 
each  respective  department ;  or,  in  other  words,  the  laws  of  celes- 
tial and  terrestrial  bodies. 

5.  Geology  comprehends  in  its  domain  all  the  facts  concerning 
the  relations  of  the  masses  which  compose  the  Earth,  its  structure, 
and  the  changes  it  has  undergone  in  time :  but  a  fuller  statement 
of  its  objects  will  be  found  farther  on. 

6.  Mineralogy  treats  of  the  individual  objects  which  compose  the 
earth,  and  the  characters  by  which  they  may  be  known. 

7.  Chemistry  has  a  special  reference  to  the  Composition  of  bodies, 
and  the  laws  of  Combination  to  which  the  elements  are  subject. 
It  determines  what  bodies  are  Simple,  and  what  are  Compound,  and 
in  what  ratios  the  elements  combine. 

8.  Palaeontology  combines   in  its  domain   the   associated   facts 
relative  to  Fossils,  whether  of  vegetable  or  of  animal  origin,  which 
are  found  in  the  sediments  or  rocks  of  aqueous  origin. 

9.  The  earliest  condition  of  the  foregoing  branches  of  know- 
ledge was  in  that  of  isolated,  or  of  disconnected   facts.     Their 
reduction  to  order  and  combination  into,  a  scheme  expressing  gene- 
ral and  fixed  relations,  elevated  these  facts  into  departments  of 
science.  * 

10.  Facts  are  accumulated  by  two  methods,  Observation  and 
Experiment;  but  their  arrangement  and  construction  into  systems 
is  by  a  process  called  Induction,  the  facts  and  experiments  consti- 


CHARACTERISTICS   OP   MAN.  15 

tuting  the  basis  by  which  the  inductive  process  is  executed.  This 
process  is  generally  defined,  as  that  by  which  general  laws  are 
inferred  from  particular  facts.  The  induction  itself  expresses  the 
general  result  or  law  which  is  established  from  the  consideration 
and  bearing  of  the  facts  observed. 

It  is  evident,  furthermore,  that  results  or  laws  require  in  us  a 
belief  in  the  uniformities  of  nature ;  or  that  like  causes  are  followed 
by  like  effects.  Without  such  a  belief,  or  unless  these  uniformities 
existed,  science  would  be  impossible.  Science,  we  may  therefore 
state,  is  founded  upon  the  uniformities  of  nature,  without  which 
our  observations  would  be  of  no  avail,  and  our  experiments  would 
be  useless. 

11.  The  explanation  of  effects  is  accounted  for,  in  general,  by 
referring  them  to  something  which,  so  far  as  we  know,  constantly  pre- 
cedes them ;  and  that  which  precedes,  is  said  to  be  the  cause.    But, 
then,  it  is  customary  to  speak  of  two  kinds  of  causes,  Physical  and 
Efficient.     The  former  is  the  law  itself,  as  the  fall  of  a  stone  to 
the  earth  is  referred  to  the  law  of  gravitation.     The  latter  implies 
intelligence,  and  is  referred  directly  to  the  Divine  will. 

12.  In  investigating  the  facts  of  all  existences,  it  is  necessary 
to  recognise  the  presence  of  both  forces  and  agents.     It  is  by  them 
that  the  uniformities  of  nature  are  usually  expressed.     What  is 
called  Gravitation  is  an  example  of  an  universal  force,  and  the  law 
of  the  movements  of  bodies  is  expressed  by  well-known  formulas, 
while  Affinity  is  a  force  which  affects  the  molecules  of  matter,  and 
disposes  them  to  combine  in  definite  ratios. 

13.  Agents  are  physical  bodies. — In  geology,  for  example,  it  is 
necessary  to  recognise  the  agency  of  fire  and  water.     Their  effects 
become  evident  to  the  senses,  and  their  operations  are  extremely 
varied.     The  action,  of  particular  forces  is  inferred  from  effects  or 
consequents. 

14.  The  kingdom  of  inorganic  matter  stands  out  prominently  by 
itself,  and  is  evidently  subjected  in  itself  to  the  action  of  physical 
forces  only.     These  are  its  highest  endowments.     The  first  step 
indicative  of  progress,  is  in  the  vegetable  kingdom,  or  in  the  domain 
of  organic  matter.     Here,  life  in  a  low  degree  is  engrafted  upon 
organization,  or  is  associated  with  it,  and  may  be  the  formative 
principle  of  organization.     It  exhibits  a  great  advance  upon  inert 
matter,  especially  when  contrasted  with  the  law  of  inertia.     Thus 
the  lowest  condition  of  life  appears  first  in  the  vegetable  kingdom, 


16  MANUAL   OF   GEOLOGY. 

where  it  is  designed  in  part  to  evolve  successive  generations  of 
beings,  to  clothe  the  earth,  and  furnish  a  supply  of  food  for 
animals.  The  life  of  the  vegetable  kingdom  is  called  Vegetative 
life;  it  is'simply  nutritive  in  its  functions.  Another  stage  far  in 
advance  of  this  is  Animal  life;  a  concomitant  of  animals.  By 
this  kind  of  life,  the  world  of  matter  becomes  known  to  us  through 
the  medium  of  the  senses.  Vegetative  life  is  a  blank,  or  is  blind. 
But  animal  life  may  be  said  to  be  engrafted  upon  what  previously 
existed;  for  vegetable  life  still  works  in  animals  in  the  nutrimental 
sphere,  precisely  as  it  does  in  vegetables.  There  is  nothing,  there- 
fore, in  the  advance  of  kingdoms  which  is  deposed.  We  also 
see  that  the  advance  of  kingdoms  is  not  by  Differentiation,  but  by 
Incrementation.  The  latter  expresses  the  law  of  progress  in  the 
kingdoms. 

15.  The  highest  concomitant  of  animal  life  in  itself  is  intellectj 
embracing  the  knowing  faculties,  which  are  dispensed  in  different 
degrees,  and  are  common  to  animals  and  man.     But  the  crowning 
stage  is  exhibited  in  the  sphere  of  man  alone,  for  there  is  engrafted 
upon  vegetative  and  animal  life  and  its  concomitant  Intellect,  Rea- 
son, and  Conscience,  with  their  concomitants  also,  which  confer  upon 
man  the  highest  boon,  immortality. 

16.  In  all  the  foregoing  stages  of  progress,  nothing  is  deposed  or 
dethroned.     The  physical  forces,  it  is  true,  are  for  the  time  being 
overridden,  but  not  left  out.    Vegetative  life  still  performs  its  office 
in  its  own  sphere.     Intellect  in  man,  though  of  a  vastly  higher 
grade  than  in  animals,  maintains  its  place,  and  the  highest  attri- 
butes we  have  named  are  the  governing  characteristics  by  which  he 
should  be  classified.     These,  reason  and  conscience,  are  the  attri- 
butes of  his  sphere,  and  place  him  above,  and  out  of  the  pale,  of  the 
so-called  animal  kingdom.     The  life  of  reason  and  its  concomitants, 
being  engrafted  upon  the  intellectuals,  if  progress  is  truly  expressed, 
exhibits  the  kingdoms  as  completing  their  progress  in  four  stages; 
advancing  from  the  inertia  of  matter,  through  vegetative  life,  to 
animal  life  and  its  engrafted  concomitants,  then  upward  to  the  life 
of  reason  in  the  soul  of  man,  becoming  thereby  the  true  character- 
istics of  his  being. 

17.  These  stages  are  recognised  in  the  geologic  periods,  and  cor- 
respond with  the  succession  of  vegetables,  animals,  and  man  upon 
the  globe :  the  kingdom  of  matter  first,  the  kingdom  of  man  last, 
the  extremes  of  the  geologic  scale. 


CHAPTER  II. 

CLASSIFICATION. 

18.  CLASSIFICATION  is  the  Systematic  Arrangement  of  bodies, 
according  to  the  governing  characteristics   discoverable   in  their 
plans,  forms,  and  structure.     The   process  is  performed  daily  by 
men  in  virtue  of  their  possessing  in  their  mental  organization  a 
classifying  principle  which  can  seize  the  governing  ideas  expressed 
in  plans,  forms,  and  structures. 

The  idea  contained  in  Classification  is  that  of  a  separation  of 
bodies  into  classes  and  subordinate  divisions,  each  individual  of 
which  belonging  to  those  classes  or  divisions,  shall  express  one  or 
more  ideas  common  to  each  respective  division.  The  foundation 
for  the  performance  of  this  function,  it  can  scarcely  be  doubted,  is 
as  much  dependent  upon  the  existence  of  governing  forms  and 
structure  in  "bodies  themselves,  as  upon  the  possession  of  the  classi- 
fying principle  in  us  -}  both  are  necessary,  and  it  is  important  that 
we  should  especially  feel  that  the  foundation  exists  in  nature ;  for 
without  this  assurance  we  shall  remain  in  doubt  whether  there  is 
really  in  nature  a  regular  plan  upon  which  her  works  are  con- 
structed. If  there  is  a  plan,  it  will  be  manifested  by  a  series  of 
characteristics  or  phenomena,  expressed  either  in  the  outward  form, 
or  their  less  obvious  inner  structures. 

19.  All  existences  may  be  classified,  but  the  bodies  which  con- 
cern us  most  are  Animals,  Plants,  and  Minerals.    These  if  classified 
are  denominated  the  Animal,  Vegetable,  and  Mineral  Kingdoms 
Each  kingdom  has  its  own  principles  of  classification,  notwithstand- 
ing the  heads  of  the  divisions  are  designated  alike  in  case  the  divi- 
sions are  admissible   or  founded  in   nature,     Taking  the  animal 
kingdom  first,  as  it  furnishes  the  best  illustration  of  a  scheme  of 
classification,  it  has  been  determined  that  there  are  four  diverse 
branches  or  plans  which  were  created  to  express  so  many  modes  of 
life  which  are  compatible  with  the  reigning  external  conditions  of 
the  globe.     Each  branch  circumscribes  all  those  existences  which 
are  constructed  upon  a  certain  plan. 

2*  (17) 


18 


MANUAL   OF   GEOLOGY. 


20.  These  plans  are  expressed  by  the  following  terms.     1.  VER- 

TEBRATA.      2.     ARTICULATA.     3.    MOLLUSCA.      4.    B-ADIATA.      It 

should  be  understood  that  these  are  not  modifications  of  one  plan, 
but  that  they  are  four  distinct  plans  j  and  to  determine  whether  a 
being  belongs  to  Vertebrates  (fig.  1),  we  have  only  to  inquire  whether 
it  has  a  Spinal  cord,  or  if  to  the  Radiata,  whether  its  organs  are  ar- 
ranged rad-i-ately  at  not.  Respecting  the  first,  we  need  not  institute 
an  inquiry  as  to  the  conditions  of  the  protecting  organ,  whether  it  is 
bone,  or  a  cartilaginous  tubej  the  inquiry  is,  whether  it  has  the 


CLASSIFICATION. 


19 


nervous  organ,  the  spinal  centre,  or  not.  In  the  latter,  the  question 
is  not  put  whether  it  has  nerves  or  not;  but  simply  into  the  radiate 
disposition  of  its  organs.  With  respect  to  the  Articulata  (figs.  2  to  4,) 

F<*'  2'  Fig.  3. 


Articulata. 


Fig.  4. 


Fig.  5. 


Mollusca.  (Nerita  Polita.) 


Articulata.  Acidaspis. 

whether  it  has  a  jointed  body  and  limbs,  or  of  Mollusca  (fig.  5), 
whether  its  body  is  soft,  having  a  peculiar  flesh  like  the  oyster. 
Other  inquiries  are  extraneous  when  the  branch  to  which  an  animal 
belongs  is  the  only  question  for  determination.  From  the  foregoing 
remarks  it  is  evident  that  a  branch  of  the  animal  kingdom  has  refer- 
ence solely  to  a  plan,  but  not  the  details  of  a  plan. 

The  figure  of  the  Lacamedea  geniculata  (fig.  6,  p.  20),  from  John- 
son, shows  both  the  closed  and  expanded  vesicles  of  the  polype,  and 
also  the  radiated  arrangement  of  the  parts  of  the  animal.  They  pro- 
duce in  growth  a  corneous  stalk  which  puts  forth  buds  something 
in  the  form  of  a  flower.  It  represents  one  of  the  orders  of  this 


20 


MANUAL   OF   GEOLOGY. 


great  branch  of  the  animal  kingdom  Radiata.  In  another  type, 
the  asteroid,  the  polype  forms  a  stony  skeleton,  which  is  known 
under  the  common  name  of  coral;  Fig.  7  represents  this  order, 
which  also  belongs  to  the  branch  Radiata. 


Fig.  6. 


Fig.  7. 


Lacsmedea  geniculat*. 


Corallum   rubrum. 

21.  Regarding,  then,  the  foregoing  statements  with  respect  to 
the  four  plans  of  organization  of  the  animal  kingdom  to  be  estab- 
lished, we  may  proceed  to  the  consideration  of  Class,  which  is  the 
next  division  below  that  of  branch.  The  word  class,  in  this  con- 
nection, means  the  highest  and  most  comprehensive  division  which 
can  be  made  in  each  respective  branch.  It  is  important  to  observe 
here,  that  the  characters  which  are  employed  should  have  reference 
to  the  plan  of  structure,  and  be  selected  with  a  view  to  express  the 
mode  by  which  Nature  executes  or  carries  out  her  plan  of  organiza- 
tion, whether  it  be  a  vertebrate,  or  any  other  plan  belonging  to  the 
kingdom.  In  each  class,  provided  there  is  an  harmonious  system  of 
construction,  we  shall  find  a  ruling  idea  expressed  in  structure,  or 
in  the  economy  of  their  systems,  which  will  run  through  the  entire 
class,  and  in  which  we  shall  find  an  unmistakable  similarity  or  homo- 
logy  in  each  member,  however  much  it  may  seem  to  differ  in  form 

In  the  first  place,  we  propose  to  illustrate  the  preceding  principle 


CLASSIFICATION.  21 

by  the  Vertebrata.  This  branch,  as  now  constituted,  contains  five 
classes  :  Mammalia,  Aves,  Reptilia,  Amphibia,  and  Pisces.  These 
have  one  characteristic ;  all  have  the  spinal  cord.  Now,  on  what 
grounds  are  these  classes  established,  or  by  what  characteristics  are 
they  so  circumscribed  that  we  have  a  right  to  distinguish  them  as 
classes  ?  We  may  demonstrate  their  right  to  this  distinction  and 
standing  by  the  following  characteristics  :  And,  firstly,  by  the 
mammals. — In  this  group,  a  system  of  organs  has  been  provided 
for  the  temporary  subsistence  of  the  young.  These  organs  are 
lactiferous  glands  which  secrete  milk,  and  which  sustain  for  a  time 
the  newborn  individual,  or  until  it  acquires  the  power  and  ability 
to  provide  for  itself.  This  characteristic  is  wanting  in  the  other 
classes.  The  name  of  the  class  expresses  its  characteristic  in  a 
condensed  form.  The  selection  of  this  characteristic  is  in  accordance, 
too,  with  the  principle  already  laid  down  It  is  a  ruling  idea,  or  a 
class  character,  being  universal  and  essential  in  the  economy  of  this 
great  division  of  beings ;  and  besides,  is  associated  with  organs  whose 
office  secures  the  continuance  of  the  species.  It  carries  out  the  eco- 
nomy of  the  plan  of  the  vertebrata.  It  is  true,  the  mammals  wear 
hair  upon  their  skin,  but  this  is  a  circumstance ;  they  could  subsist 
without  it ;  but  milk  glands,  with  their  appendages  in  this  plan  of 
organization,  are  made  to  express  the  most  important  idea  of  the 
class.*  But  the  idea  of  the  class  is  founded  upon  soft  parts  which 


*  In  one  sense  it  is  not  the  activity  of  the  milk  glands  which  constitutes  a 
mammifer,  for  the  individuals  of  this  great  family  are  born  mammifers ;  they  are 
so  prior  to  the  time  when  they  hecome  essential  elements  in  the  animal  economy. 
When  we  speak  of  predominating  organs  or  elements  in  the  structure  or  economy 
of  living  beings,  our  meaning  is,  that  they  are  common  or  constant  to  the  indi- 
viduals composing  the  branch,  class,  order,  etc.,  in  the  adult  state.  Perhaps  we 
might  justly  say,  that  which  constitutes  the  essentials  of  a  being  is  invisible,  and 
inappreciable  to  our  senses.  The  principle  in  the  egg  of  a  fowl,  which  evolves 
the  fowl,  is  inappreciable,  and  is  not  dependent  upon  organs,  because  that  would 
place  the  effect  before  the  cause.  The  egg  of  a  fowl  evolves  a  fowl,  and  not  a 
reptile,  because  it  receives  the  principle  which  evolves  it  from  the  parent,  and 
we  can  go  no  farther  than  to  say  that  it  is  the  gift  of  the  CREATOR.  The  Creator 
imparted  to  each  species  its  specific  force,  inappreciable  to  us,  by  and  in  obedi- 
ence to  which  each  definite  species  is  evolved  in  its  sphere,  and  this  gift  secures 
the  permanence  of  species  for  all  time,  and  prevents  their  coalescence;  while  at 
the  same  time  they  possess  certain  flexibilities  of  character  which  enables  them 
to  conform  to  a  range  of  circumstances  which  it  was  foreseen  they  would  be 
subjected  to;  and  hence  these  variables,  as  they  may  be  called,  are  a  part  and 
parcel  of  family  or  of  their  specific  characters. 


22 


MANUAL   OF   GEOLOGY. 


never  exist  in  fossils;  hence  it  is  necessary  to  know  more  of  the 
organization  of  mammals  than  it  is  possible  to  learn  from  the  soft 
parts  alone,  and  we  must  find  in  their  bones  those  characters  which 
belong  to  them  as  a  class.  Such  characters  exist  and  become 
available  for  this  purpose;  for  example,  the  lower  jaw  of  all  mam- 
mals is  in  one  solid  piece,  us  seen  in  fig.  8.  Whereas,  the  jaws  of 
reptiles  and  fish  are  composed  of  many,  as  in  fig.  9 ;  besides — 

Fig.  8.  Fig.  9. 


Skull  and  Jaw  of  the  Tiger. 

The  molar  teeth  of  mammals,  too,  have  more 
than  one  root.  Fig.  10  (see  p.  23).  Indeed, 
it  is  doubtful  whether  the  reptile  has  molars 
at  all,  since  the  back  teeth  have  only  one 
root.  (Fig.  9.  A  large  back  tooth  elevated 
to  show  that  it  has  a  single  root,  as  at  a.) 
From  the  foregoing  facts  it  will  be  seen  that 
some  of  the  details  of  the  classes  which  lie 
at  the  foundation  of  the  great  divisions  of 
the  branches,  exist  both  in  the  soft  and  hard 
parts  of  animals.  The  Zeuglodon  (fig.  1 0)  has 
a  sauroid  form,  and  was  taken  for  a  saurian 
when  first  discovered;  yet  its  teeth,  from 
their  double  roots  and  the  convexity  of  its 
condyles,  prove  it  to  be  a  mammal.  In  the 
highest  mammals  there  is  always  a  complete 
series  of  molars,  pre-molars,  canine,  and  in- 
cisor teeth,  as  in  the  Chimpanse  (fig.  11). 
There  is  also  a  wide  space  between  mammals 
and  birds.  The  latter  have  mandibles  and 
no  teeth :  fig.  12  (see  p.  24) ;  the  mandibles 


» .  ^ 

•  \ 


jaw  of  an  Alligator,  with  It* 
sutures  separating  its  pieces. 


CLASSIFICATION. 

Fly.  10. 


23 


Zeuglodon  Tooth  with  its  double  roots. 

Fig.  11. 

of  the  eagle,  or  fish  hawk ;  but 
we  know  a  family  of  mammals 
in  New  Holland  which  have 
the  mandibles  of  a  bird;  but 
their  feet  differ  from  birds,  and 
hence  we  take  into  consideration  ,.^ 
the  character  of  the  feet  (fig. 
13,  p.  24).  It  would  occupy 
too  much  space  to  go  farther 
into  particulars  and  point  out 
differences  between  the  Mono- 
tremata  and  birds. 

It  is  more  difficult  to  find  marks  which  distinguish  reptiles,  am- 
phibians, and  fishes,  especially  when  we  possess  only  organic 
remains.  True  reptiles,  however,  have  only  one  condyle,  whereas 
the  amphibia  have  two  (fig.  14,  p.  25).  A.  showing  the  base 


24 


MANUAL   OF   GEOLOGY. 


Mandibles  of  the  Fish  Hawk. 
Fig.  13. 


of  the  skull  of  the 
Dictyocephalus,  a  rep- 
tile which  belongs  to  * 
the  Labyrinthodonts, 
all  of  which  have  also 
double  condyles. 

Their  bones,  how- 
ever, differ  in  struc- 
ture, and  under  the 
microscope  the  re- 
mains of  fish  may 
be  distinguished  from 
reptiles  by  the  form 
of  the  bone  cell, 
which  will  be  aoticed 
farther  on. 

One  of  the  distin- 
guishing characters 
of  amphibians  is  their 
naked  skin.  They 
have  neither  scales 
nor  plates,  and  be- 
sides they  undergo  a 
kind  of  metamorpho- 
sis which  is  unknown 
in  the  other  classes. 
There  is  little  diffi- 
culty in  classifying 
animals  as  they  are  commonly  presented  to  us.  We  may  see  at 
once  the  difference  between  a  fish  and  a  lizard  or  frog,  a  bird  and 
a  quadruped ;  it  is  more  difficult  to  point  out  distinguishing  cha- 
racteristics where  two  classes  approach  each;  or  in  the  sauroid 
fishes,  and  certain  saurians,  especially  where  the  student  has  to  deal 
with  mere  fragments  of  fossils.  These  require  careful  study,  and 
we  have  no  space  to  devote  to  specialities  of  this  kind. 

22.  Order  takes  the  next  rank  below  class.  It  is  a  subdivision 
of  classes,  and  hence,  it  would  be  an  error  to  employ  those  charac- 
ters which  relate  to  the  mode  in  which  a  plan  of  structure  is 
carried  out.  It  derives  its  characteristics  from  the  details  of  the 


Foot  of  the  Fish  Hawk. 


CLASSIFICATION. 


25 


Fig.  14. 


/• 


general  organs,  or  the 
differences  existing 
among  them  in  each 
class  respectively.  For 
illustration,  we  may 
cite  the  class  Reptilia 
— a  scale-bearing,  and 
at  the  same  time  an 
air-breathing  verte- 
brate. The  class  con- 
tains animals  whose 
bodies  are  protected 
by  a  box  or  shield 
above  and  below,  con- 
nected laterally  by  a 
bridge.  These  form 
one  order  in  the  class, 
and  are  named  the 
Testudinata^T  turtles. 
Another  group  of  rep- 
tiles, that  of  tSauria, 
have  elongated  bodies, 
and  a  mouth  furnished 
with  teeth;  and  an- 
other, Ophidia,  with 
vermiform  bodies  and 
destitute  of  feet,  or 

Who  employ  their  ribs.  Labyrinthodont  with  its  double  condyle,  a  a. 

as  a  locomotive  apparatus.  All  these  modifications  of  structure 
illustrate  modes  in  which  the  orders  of  the  class  differ;  which 
differences  constitute  a  basis  for  the  establishment  of  the  orders 
themselves. 

The  ordinal  characters  being  modes  of  expression,  by  which  the 
class  arrangements  are  carried  out,  we  can  scarcely  fail  to  observe 
that  they  necessarily  lead  to  many  details  of  structure  which  are 
truly  ordinal  also.  Thus,  in  the  turtles,  an  important  modification 
of  the  muscular  system  follows  from  the  peculiar  protection  of  the 
shield :  no  movements  are  required  of  the  spine  except  of  the 
neck  and  tail ;  and  those  of  the  neck  are  executed  in  a  mode  quite 
peculiar.  On  the  contrary,  the  extreme  of  the  muscular  arrango- 
3 


26  MANUAL   OP   GEOLOGY. 

ments  exist  in  the  serpents,  whose  spinal  column  is  extremely 
movable,  and  whose  locomotive  apparatus  requires  a  combination 
of  spinal  and  costal  muscles.  The  ordinal  characters  are  to  the 
class,  what  the  class  characters  are  to  the  branches;  and  from 
these  and  other  considerations  it  is  evident,  that  as  the  ordinal 
characters  have  a  separate  and  distinct  office,  or  indeed  perform 
the  highest  functions  of  life  in  the  individual;  they  are  natural 
appointments. 

Formerly  frogs,  toads,  and  salamanders  were  placed  in  the  class 
Reptilia,  constituting  an  order.  They  have  been  separated,  and 
now  form  a  class  denominated  Amphibia.  Their  naked  skins,  and 
their  metamorphoses,  entitle  them  to  the  position  they  now  occupy 
in  our  systems.  They  are  inferior  in  rank  to  reptiles,  and  are 
more  closely  allied  to  fishes. 

But,  to  be  more  particular,  Order  may  be  illustrated,  1.  by  refer- 
ence to  the  class  of  birds.  Some  of  the  details  which  express 
ordinal  characters  will  be  found  in  the  variable  forms  of  mandibles 
and  the  locomotive  organs — the  legs  and  feet.  Thus  the  birds  of 
prey,  the  Raptores,  have  sharp  hooked  bills,  and  feet  with  sharp 
claws  for  seizing  and  holding  their  prey,  as  in  fig.  12  and  13.  The 
order  Scansores,  or  climbers,  have  straight  and  somewhat  wedge- 
form  bills  of  great  strength,  and  feet  with  four  toes ;  two  before 
and  two  behind,  which  fit  them  for  climbing,  as  in  figs.  15  and  16. 

The  order  Natatores, 

Fig.  15.  Fig.  16. 

or  swimmers,  have 
feet  wholly  or  part 
webbed,  as  fig.  17. 
Another  order,  the 
Grallatores,  have 
long  naked  legs,  fit- 
ted for  wading,  as 
the  Herons.  They 
have  long  sharp  tri- 
angular bills  for  seiz- 
ing fish ;  others 
have  slender  bills  for 
exploring  the  mud 

Bill  of  the  Woodpecker.  Foot  of  the  Woodpecker.  for    WOrmS,  aS    in    the 

Snipe,  fig.  18.     The  foregoing  embrace  some  of  the  details  relative 
to  some  of  the  orders  in  the  class  Aves.     These  may  be  said  to 


CLASSIFICATION. 


27 


Fig.  17. 


Fig.  18. 


Foot  of  the  Duck. 

include  the  most  important  details  belonging  to  the 
class. 

Mollusks  are  divided  first  into  Mollushs  proper,  as 
snails,  clams,  oysters,  &c.,  and  Bryozoa ;  the  latter 
of  which  furnish  certain  general  resemblances  to  the 
radiata,  as  in  fig.  19.  But  their  digestive  organs  are 

Fig.  19.  Fig.  20. 


Snipe. 


molluscan,  their  ori- 
fices for  the  recep- 
tion of  food  and 
the  discharge  of 
excrements  are  dis- 
tinct, as  at  d;  a 
being  the  oesopha- 
gus, and  their  mi- 
nute cells  are  not 
septate,  as  in  the 
polypes.  The  first 
and  highest  order 
of  mollusks  are  the 
Cephalopoda,  as  re- 
presented in  fig.  20. 
Their  feet  or  arms 
surround  the  head 
and  are  provided  with  suckers.  The  Gasteropods  move  upon  a  broad 
foot,  placed  usually  beneath,  as  fig.  3.  The  Pteropods  have  their 
organs  of  locomotion  wing-like  and  placed  upon  the  sides  of  their 
heads,  as  fig.  21.  The  Tunicata  are  soft  animals,  or  without 


Cephalopod. 
Octopus  hawaiensis. 


28 


MANUAL   OF  GEOLOGY. 


Fig.  21. 


Fig.  22. 


Pteropod. 

Creseis  subulata. 


Fig.  23. 


live    in 

families.  They  are  enclosed  in 
a  sac,  and  have  never  been  found 
in  a  fossilized  state,  Fig.  22. 
The  arrows  represent  the  course 
of  the  food. 
•  The  Bracliiopods,  or  Pallio* 

Fig.  24. 


Spirifer  striatas. 
Fig.  25 

branchiata,  are  equally 
distinct,  as  an  order, 
from  the  preceding. 
They  are  inequivalve 
bivalves;  a  large  valve 
being  applied  over  the 
abdomen  and  a  small 
one  to  the  back ;  and 
hence  are  distinguish- 
ed as  ventral  and  dorsal  valves.  The  former  has  often  a  perforated 


Lingnla  anatina. 


Atrypa  retlcnlaris. 


CLASSIFICATION. 


29 


beak  from  which  issued  a  byssus  by  which  the 
animal  attached  itself  to  some  foreign  body: 
fig.  23  shows  the  attachment  of  the  Lingula,  a 
genus  of  this  order.  The  mollusks  of  this 
order  were  also 'supplied  with  an  internal  cal- 
careous skeleton  in  the  form  of  coils,  loups,  &c., 
as  represented  by  fig.  24,  showing  the  spiral 
of  the  genus  Spirifer  (Spirifer  striatus),  and  fig. 
25,  the  spiral  cones  of  the  Atrypa  reticularis. 
Some  of  the  genera  of  this  order  were  free : 
that  is,  they  were  not  attached  to  a  foreign 
body.  The  Brachiopoda  are  the  most  ancient 
mollusks  known  ;  they  began  their  existence  in 
the  oidest  sediments,  and  have  continued  down 
to  the  present  epoch. 

Fig.  27. 


Fig.  26. 


Gasteropod. 


Tritonium  Anglicum. 


Cytherea. 
Acephala. 

We  should  not  pass  over  the  common  divisions  of  mollusks  into 
univalves  and  bivalves,  or  with  shells  consisting  of  one  and  two 
valves  (fig.  26  and  27),  the  Cytherea,  fig.  27,  with  its  palleal  line 
3* 


30 


MANUAL   OF   GEOLOGY. 


Fig.  28. 


forming  a  sinus,  as  in  the  upper  valve,  upon  the  left,  and  its  two 
muscular  impressions  placed  at  the  extremes  of  the  line.  Other 
bivalves  have  the  palleal  line  continuous  and  without  a  sinus ;  and 
as  to  the  muscular  impressions,  many  have  one  only,  as  it  is  seen  in 
the  oyster  and  scallop. 

The  fish  were 
divided  by  Agas- 
siz  into  four 
orders,  being  go- 
verned by  the 
form,  structure, 
and  composition 
of  the  scale.  Fig. 
28,  a,  the  ganoid 
scale,  of  a  rhom- 
bic form,  and 
covered  with 
enamel ;  fr,  the 
placoid  scale, 
furnished  with 


hooks 


the 


Heterocercal  Tail. 


Homocercal  Tail. 


ctenoid      scale 
of    the     perch ; 

d,  the  cycloid  .scale  of  the  shad ;  the  two  last  kinds  are  corneous 
and  flexible.  The  two  former  belong  mostly  to  ancient  fishes ;  the 
two  latter  are  comparatively  modern,  and  did  not  appear  until  the 
cretaceous  period. 

The  form  of  the  tail  of  fishes  furnishes  important  characters. 
The  organ  is  divided  into  two  lobes.  When  the  upper  lobe  is 
larger  than  the  lower,  it  is  said  to  be  heterocercal,  fig.  29  :  when  the 
lobes  are  equal,  or  nearly  so,  or  the  spinal  column  terminates  at  the 
base  of  the  lobes,  it  is  homocercal,  as  in  fig.  30. 

23.  In  proceeding  from  the  more  to  the  less  general  divisions,  it 
is  maintained  by  distinguished  naturalists,  that,  family  naturally 
succeeds  order ;  that  families  are  often  groups  under  an  order,  cir- 
cumscribed by  characteristics  more  or  less  well  defined.  A°-assiz 
confines,  however,  family  characteristics  to  form,  not  simply  shape, 
but  form,  growing  out  of  structural  peculiarities ;  still,  the  mean- 
ing is  closely  allied  to  shape,  which  is  due  to  the  proportion  of 
parts ;  or  it  may  be  expressed  by  saying,  that  it  is  due  to  the  rela- 
tive developments  of  parts,  as  to  size  and  position,  and  hence,  the 


CLASSIFICATION.  31 

Fig.  31.  Fig.  32.  Fig,  33. 


Bos.  insectivora. 

Cervus.         Herbivora.  Dromatherium. 

characteristic  is  one  of  likeness  dependent  on  form  and  proportion 
of  parts.  As  such  characteristics  strike  one  at  the  first  glance,  it 
is  evidently  an  outward  character,  and  distinguishable  without  the 
necessity  of  dissection.  For  example,  the  bodies  of  groups  of 
turtles  may  be  comparatively  high  and  oval,  or  round — or  they 
may  be  depressed  and  circular — each  form  would  constitute,  if  the 
principles  have  been  stated  aright,  families,  under  the  order 
Testudinata. 

The  families,  however,  as  constituted  under  Mollusca  by  the 
most  popular  writers,  do  not  seem  to  be  founded  on  the  principle 
of  form  alone ;  and  we  may  remark,  that  it  is  impossible  now  to 
restrict  this  characteristic  to  family — botanists  use  it  so  constantly 
in  specific  descriptions,  as,  form  of  a  leaf,  seed,  or  root,  &c.,  that  it 
can  scarcely  be  dispensed  with.  There  are  embryonic  forms,  and 
generic  and  specific  forms ;  as  well  as  forms  which  are  peculiar  to 
rarieties.  If  the  word  form,  is  restricted  by  qualifications,  its  use 
will  not  lead  to  confusion  in  description.  But  if  we  substitute 
likeness  for  form,  or  relative  proportion  and  position  of  organs,  our 
error  will  be  but  trifling;  for  it  is  likeness  which  we  seize  upon  at 
our  first  glance,  and  not  form. 

24.  Families  and  sometimes  orders,  without  family  division,  are 
divided  into  Genera.  A  genus  finds  its  characteristics  in  what 
Agassiz  has  termed  complication  of  structure.  To  us  the  expres- 
sion is  obscure,  but  by  reference  first  to  several  genera  we  may  catch 
a  glimpse  of  his  meaning.  In  the  class  mammals  we  find  the  orders 
Carnivora  and  Herbivora  :  the  first  flesh  (fig.  5),  and  the  last  '(fig8* 
31  and  32),  herb  eaters;  and  hence  their  feeding  is  very  diverse, 
and  their  masticating  and  digestive  apparatus  are  necessarily  dis- 
similar. But  carnivora  differ  among  themselves  in  certain  organs. 
There  are  the  genera,  Felis,  and  Canis ;  the  cat  and  dog  both  are 
flesh  feeders,  and  both  have  teeth  adapted  to  the  purpose  ;  but 
their  number  and  characteristics  differ.  In  flesh  feeders  the  crown 
terminates  in  cutting  edges,  as  in  the  tiger.  Their  eyes  and  feet 


32  MANUAL   OF   GEOLOGY. 

differ,  which  differences  become  fitted  to  their  habits.  One  is  noc- 
turnal, the  other  not.  One  watches  for  its  prey  and  seizes  it 
with  a  bound;  the  other  openly  pursues  until  it  is  overtaken. 
Their  class  characters  are  the  same :  they  are  mammals.  Their 
ordinal  characters  are  alike :  they  feed  upon  flesh ;  but  then  the 
number  of  their  teeth,  together  with  their  forms,  differ;  the  nails 
of  their  toes  differ :  in  one  they  are  retractile  and  kept  sharp  for 
tearing  their  prey.  They  differ  in  their  whole  economy,  and  these 
differences  grow  out  of  peculiarities  of  structure ;  and  these  pecu- 
liarities are  generic  characters,  or  complications  of  structure,  as 
called  by  Agassiz.  The  cat  is  a  higher  grade  of  carnivora  than  the 
dog.  To  make  out  a  cat,  we  examine  its  eye,  its  form  of  head, 
which  is  in  part  due  to  large  muscles,  its  teeth,  its  feet  and  claws, 
its  shoulders,  and  those  characteristics  which  grow  out  of  the  pecu- 
liarities of  these  organs,  and  we  have  the  cat,  or  genus  fells,  any 
cat,  but  not  a  particular  cat,  as  the  cougar,  lion,  tiger,  and  domestic 
cat.  The  same  may  be  said  of  Canis  or  Ursus,  or  the  plantigrade 
animals.  We  find  characters  which  circumscribe  groups ;  not  indi- 
viduals, but  much  more  than  individuals.  The  Imectivora  are 
closely  allied  to  the  carnivora.  Their  molars  bristle  with  points,  as 
in  fig.  33.  The  Rodentia  have  two  cutting  teeth  in  front  in  each 
jaw,  as  the  beaver,  squirrel,  and  hare. 

25.  The  last  and  principal  division  which  succeeds  genus  is 
Species.  It  is  defined  abstractly  by  the  late  Prof.  Morton  to  be  a 
Primordial  Organic  Form.  If  the  beings  to  which  species  have 
reference  are  taken  into  view,  it  may  be  defined,  a  "  group  of  iden- 
tical individuals,  each  of  which  is  the  representative  of  the  species." 
Morton's  definition  is  open  to  the  objection  that,  in  certain  ques- 
tionable cases,  it  is  impossible  to  determine  whether  the  form  is 
primordial,  or  not.  As  it  regards  the  latter,  it  is  not  agreed,  and 
probably  never  will  be,  what  differences  in  character  are  admissible 
without  destroying  the  idea  of  identity.  Those  differences  which 
are  due  to  food,  climate,  or  which  are  developed  under  new  circum- 
stances, do  not  destroy  identity  even  though  they  become  heredi- 
tary. That  differences  do  spring  out  of  a  combination  of  circum- 
stances and  are  transmitted  to  offspring,  is  admitted  by  all  observers. 
But  questions  have  arisen  with  respect  to  differences  in  beings 
which  were  acquired  before  the  historical  period,  if  acquired  at  all, 
and  hence  questions  arise  respecting  their  identity.  One  class 
maintaining  that  these  differences  are  those  which  are  primordial 


CLASSIFICATION.  33 

or  conferred  upon  them  when  created.  Others  maintain,  on  the 
contrary,  that  such  differences  have  originated  in  the  stock  posterior 
to  their  creation,  from  a  combination  of  circumstances,  and  are  of 
such  a  nature  as  to  become  transmissible  to  their  offspring.  This 
view  is  maintained  by  facts  of  a  similar  kind,  and  on  the  ground 
that  changes  have  taken  place  within  the  historical  period  equally 
remarkable. 

But  the  nature  of  a  species,  or  the  question  what  a  species  is, 
has  been  presented  from  another  point  of  view,  the  potential  point, 
as  expressed  by  Dana,  who  in  a  communication  to  the  Scientific 
Association,  at  its  meeting  at  Montreal  in  1857,  maintains  that 
species  is  essentially  represented  by  force.  Thus,  in  inorganic 
nature,  hydrogen,  an  element,  is  represented  by  one,  and  oxygen 
by  eight,  and  in  all  combinations  of  oxygen  this  number  represents 
the  species  oxygen  ;  or,  in  case  of  combination  of  oxygen  with 
hydrogen,  the  result,  water,  will  be  8-j-l  =  9,  which  last  number  is 
the  resultant  of  the  force  of  affinity.  So  also  it  is  maintained,  on 
the  same  ground,  that  force  is  at  the  foundation  of  the  idea  of  species 
in  the  organic  kingdom.  The  force,  for  example,  of  the  germ-cell, 
developes  the  being  with  its  organs  successively ;  or  evolves  by  its 
force  a  new  individual,  that  force  operating  as  definitely  and  cer- 
tainly in  each  branch,  class,  order,  genus,  and  species,  as  in  the 
inorganic  kingdom,  where  we  can  express  the  force  arithmetically; 
and  hence,  in  both  kingdoms,  the  idea  of  species  is  based  on  "  a 
specific  amount  of  concentered  force  defined  in  the  act  or  law  of 
creation."  A  question  may  arise  here,  whether  the  idea  of  species, 
as  maintained  by  Dana,  is  not  something  back  of  or  behind  the  true 
one ;  for  instance,  whether  in  the  case  of  water,  the  true  idea  of 
the  species,  water,  is  not  to  be  taken  from  water  itself,  rather 
than  from  8-f-l  j  and  so  of  organic  beings,  whether  the  resultant  of 
the  force  of  the  germ-cell  which  evolves  the  new  individual  is  not 
the  species,  rather  than  the  evolving  force  or  power  which  certainly 
lies  back  and  behind  the  individual  evolved.  At  any  rate,  there  is 
a  distinction  between  the  evolving  force  and  the  resultant  of  that 
force;  and,  practically,  the  resultant  is  the  object  which  furnishes 
the  phenomena  by  which  species  are  defined  and  circumscribed. 

A  definition  of  a  species  belonging  to  the  organic  kingdoms 
cannot  be  fully  expressed  in  a  few  diagnostic  characters ;  inasmuch 
as  it  involves  genealogical  descent  and  perpetual  fertility;  certain 
relations  as  to  time  and  space,  to  duration  and  place,  mental  organi 


34  MANUAL   OF   GEOLOGY. 

zation  and  unity  of  thought,  food,  habits,  shape  of  organs,  color 
and  ornament.  Where  identity  extends  to,  or  includes  all  of  these 
points,  and  we  find  them  common  to  a  group  of  individuals,  we 
may  pronounce  those  individuals  one  species. 

A  species  never  changes  into  another  species,  for  a  very  good 
reason ;  it  is  derived  from  the  germ-cell  of  parents,  and  hence  is 
endowed  with  a,  parental  force.  In  order  to  effect  a  transformation 
of  a  species,  it  would  require  (if  the  expression  is  allowable)  a 
new  creation,  or  a  new  endowment  unknown  to  the  species,  or,  in 
other  words,  species  in  all  cases  are  continued  developments  of 
germs,  endowed  with  a  specific  force ;  and  hence  a  gerrn  cell  has  no 
other  force  than  that  derived  from  the  parent,  or  what  it  has 
received.  Specific  force  is  a  constant  in  nature,  imparted  to  a  cell 
by  previously  existing  beings ;  and  hence  it  is  unnecessary  to  go 
into  detailed  historical  observations,  since  we  know  that  no  organ- 
ism is  ever  developed  independently  of  a  cell,  and  which  is  univer- 
sally the  product  of  parentage ;  both  history  and  physiology  support 
each  other  upon  this  question. 

26.  Varieties  originate  in  the  individuals  of  a  species,  endowed  with 
limited  differences  from  the  common  type,  which  become  permanent. 
The  most  striking  varieties  have  sprung  up  under  the  influence  of 
domestication,  though  in  the  vegetable  kingdom  they  have  been 
observed  outside  of  man's  influence,  but  not  necessarily  multiplied, 
or  extending  beyond  the  individual.     The  seed  of  varieties  rarely 
reproduce  the  variety;  it  requires  the  cellular  tissue  as  cuttings  to 
effect  a   continuance  of  the  variety;  though  in  the  cereals  the 
varieties  are  propagated  by  the  sexual  organs.     In  the  apple,  pear, 
&c.,  it  is  the  identical  cellular  tissue  which  is  reproduced  in  the 
fruit  by  cuttings  or  buds,  which  is  a  part  of  the  organization  which 
is  uninfluenced  by  the  pollen. 

27.  Identity   of  character   involves   resemblance    or   likeness ; 
as  the  word  resemblance  is  generally  used,  it  lies  at  the  foundation 
of  classification ;  for  in  every  division  it  will  be  noted,  that  there 
are  certain  common  resemblances  existing  in  order  to  make  out 
the  large  or  minor  divisions  of  a  kingdom. 

There  are,  however,  resemblances  of  two  kinds ;  one,  which  is 
proximate,  and  which  belongs  to  individuals  of  one  stock,  or 
which  is  genealogical ;  and  another  which  is  remote,  and  is  really 
only  typical ;  it  belongs  to  the  type.  In  the  first  the  resemblance 
is  one  of  relationship,  in  kindred ;  in  the  other  it  is  simply  typical 


CLASSIFICATION.  35 

or  of  an  approximate  kind,  there  is  no  relationship.  Specific 
character,  it  will  be  perceived,  takes  in  a  wide  range  of  expression ; 
and  there  remains  still  one  field  of  research  for  the  exhibition  of 
specific  character,  which  is  often  of  the  utmost  importance.  It  is 
the  development  of  the  embryo.  The  evolutions  of  the  embryo 
in  the  same  species  are  identical  in  all  respects ;  the  force  of  the 
germ-cell  evolves  by  law,  and  the  respective  changes  indicate  as 
certainly  as  possible  the  species ;  for  the  changes  or  evolutions  of 
the  embryo  have,  at  every  stage,  reference  to  species,  not  class, 
order,  genus,  but  entirely  to  species.  Hence  we  may  employ  em- 
bryonic changes  as  indicative  of  species;  or  we  may  employ  the 
resultant  of  embryonic  forces  as  indicative  of  species.  If,  how- 
ever, every  stage  in  the  evolution  of  the  embryo  points  to  the 
species,  the  resultant  is  not  only  representative,  but  is  the  species 
itself,  and  should  be  invested  with  specific  attributes  and  characters. 
It  is  representative  so  far  as  class,  order,  and  genus  are  concerned, 
but  it  is  also  in  itself  species,  and  any  individual  is  invested  with 
a  representative  character,  which  extends  upwards  through  all  stages 
of  life,  the  specific,  generic,  and  ordinal,  ending  in 'the  branch  to 
which  it  belongs.  It  has  no  relations  except  those  of  the  highest 
kinds  to  the  branches  from  which  it  is  excluded  on  the  ground  of 
difference  of  plan  of  organization. 

A  Synopsis  of  Classes  and  Orders  belonging  to  the  Animal 
Kingdom. 

The  Mammals  are  divided  into  two  sub-classes :  the  Monodelphic  Mammifers 
and  the  Didelphic  Mammifers.     The  first  contains  twelve  orders. 
I.   SUB-CLASS — MONODELPHIC  MAMMIFERS. 

1.  The  Quadrumana,  or  monkeys. 

2.  The  Cheiroptera,  or  bats. 

3.  The  Insectivora,  insect  eaters. 

4.  The  Carnivora,  flesh  feeders. 

5.  The  Rodents — rat  beaver. 

6.  The  Edentata,  no  incisive  teeth. 

7.  Proboscideans — elephants  and  mastodons. 

8.  The  Pachyderms — pig,  hippopotamus. 

9.  Ruminants — ox,  deer. 

10.  Sirenoides,  pisciform,  and  destitute  of  posterior  members — dugong. 

11.  Zeuglodon,  only  known  in  the  fossil  state;   pisciform,  teeth  numerous j 
molars  trenchant  and  denticulated. 

12.  Cetaceans,  teeth  conical  or  none,  pisciform,  destitute  of  posterior  mem- 
bers— whales,  <fcc. 


36  MANUAL   OP   GEOLOGY. 

II.     SUB-CLASS — DIDELPHIC   MAMMIFERS. 

1.  Marsupials,  flesh  feeders;  young,  occupying  an  exterior  pouch  at  an  early 
day — opossum  and  kangaroo. 

2.  Marsupials,  vegetable  feeders. 

3.  Monotremata ;  supplied  with  a  corneous  beak,  or  mandible,  one  opening 
for  the  alimentary  canal  and  urinary  and  genital  organs,  teeth  none  or  abnormal. 

A  Synopsis  of  the  Class  Reptilia. — 6  Orders. 

1.  Testudinata,  or  turtles. 

2.  Sauria,  contains  three  families :   1.  Dinosaurs;  long  bones  partially  hollow 
like  the  mammals,  and  with  a  sacrum  composed  of  5  bones — iguanodon,  Ac. 
2.  Crocodilians.     3.  Lacertians. 

3.  Pterodactyles,  flying  lizards. 

4.  Enaliosaurs,  marine  lizards,  furnished  with  paddles — ichthyosaurus,  Ac. 

5.  Labyrinthodonts,  teeth  remarkable  for  their  complex  structure.    The  skull 
has  the  double  condyle  of  the  batrachian. 

6.  Ophidians,  or  serpents. 

Class  Amphibia. — 3  Orders. 

1.  Batrachia  anoura,  or  frogs,  destitute  of  a  tail   in  the   adult  state,  skin 
naked. 

2.  Batrachia  u/odeles,  tail  in  the  adult  state,  as  in  the  salamanders. 

3.  Cecilia,  serpentine  form,  and  destitute  of  external  limbs,  unknown  in  the 
fossil  state. 

Classification  of  Fish  after  Pictet. 

He  admits  the  following  orders  arranged  under  two  sub-classes. 

I.  SUB-CLASS — TELEOSTEANS. 

1.  Ctenoid,  scales  of  ctenoid  type. 

2.  Pleuronectes,  head  unsymmetrical,  scales  of  the  ctenoid  type — flat  fishes, 
as  the  flounder. 

3.  Cycloides,  acanthopterigian ;  scales  rounded,  smooth,  and  sometimes  sinuate, 
anterior  dorsal  rays  spinous. 

4.  Cycloides  malacopterigian,  dorsal  rays  soft. 

5.  Siluroids,  soft  rayed  and  abdominal,  without  scales,  skin  naked  or  cui- 
rassed — cat-fish. 

6.  Plectognatb.es,  skin  hard  or  plated — balistes,  diodon. 

7.  Lophobranches,  body  cuirassed,  branchia  in  tufts,  rounded,  disposed   in 
pairs — sygnathus. 

II.  SUB-CLASS — GANOIDES. 

1.  Ganoides  cycloferes ;  it  contains  four  families  :  amides,  leptolepides,  cela- 
canthes,  and  holoptichides. 

2.  Ganoides  rhombiferes,  scales  rhombic.     3.  Holopleurides,  skeleton  bony, 
body  furnished  with  plates  disposed  along  the  back  and  flanks.    4.  Ganoides  cui- 
rasses, skeleton  cartilaginous,  without  scales  covered  often  with  bony  plates ;  it 
contains  three  families  :  1.  Cephalaspides.     2.  Sturiones  or  sturgeons.     3.  Spatu- 
larides,  body  naked.     This  sub-class  evidently  contains  a  heterogeneous  assem- 
blage of  fishes. 


CHAPTER  III. 

CLASSIFICATION    CONTINUED. — VEGETABLE   AND    MINERAL 
KINGDOMS. 

28.  THE  vegetable  kingdom-  seems  to  have  been  created  upon  two 
plans,  or  to  be  evolved  in  two  distinct  branches.     The  first,  the 
seec?-bearing  plants,  and  the  second  the  spore-bearing  plants. 

29.  The  seed-bearing  branch  may  be  divided  into  Polycotyledons, 
Monocotyledons ,  and  Dicotyledons,  which  are  regarded  as  classes. 

The  spore-bearing  are  divided  into  Thallogens  and  Acrogens,  which 
appear  also  to  be  entitled  to  the  rank  of  classes.  The  Poly  cotyledons 
contain  the  coniferas,  or  class  of  pines.  The  Monocotyledons,  the 
cycads.  The  Dicotyledons,  when  trees  are  considered,  form  a  class 
to  which  all  our  fruit  trees  belong,  and  also  a  large  proportion  of 
the  forest  trees  and  shrubs,  of  course  excluding  the  pines. 

30.  The  Thallogens  include  marine  plants,  which  are  generally 
known  as  sea  weeds  ;  the  fungi  or  toadstools,  as  they  are  familiarly 
called  j  and  the  lichens,  or  leathery  foliaceous  plants,  which  grow  on 
rocks,  trunks  of  trees,  fences,  &c. 

31.  The  Acrogens  comprehend  the  mosses  proper,  the  ground- 
pines,  or  club-mosses,  and  sometimes  called  Lycopodites,  and  the 
ferns.     The  two  former  have  small  veinless  leaves,  the  latter  have 
veins  which  are  forked. 

32.  Seed-bearing  plants  may  be  viewed  from   another  point: 
first,  as  to  the  growth  of  the   stem.      In  this  feature  they  pre- 
sent two  kinds  of  growth.     1.  Those  which  form  annually  a  layer 
of  wood   upon  the  outside.     They  are    the   Exogens,  or  outside 
growers,  as  the  maple  and  apple.      2.  Those  which  grow  from  the 
inside,  or  Endogens,  as  palms,  Indian  corn,  &c.    We  may  also  notice 
their  leaves,  particularly  with  respect  to  the  distribution  of  veins. 
The  dicotyledonous  plants,  or  exogens,  exhibit  veins  which  branch 
in  various  ways,  or  they  are  said  to  be  reticulated.     The  endogens, 
or  monocotyledonous  plants,  have  parallel  veins.    From  these  com- 

4  (37) 


38  MANUAL   OP   GEOLOGY. 

mon  characteristics  the  student  is  furnished  with  a  clue  to  the  class 
to  which  a  plant  belongs,  if  he  has  a  seed,  a  leaf,  or  a  fragment  of  a 
stem.  The  spore-bearing  plants  have  exclusively  a  cellular  struc- 
ture, except  the  ferns,  which  have  spiral  vessels;  in  consequence 
of  which,  as  a  great  division,  they  have  been  called  Cellulares,  in 
contradistinction  to  Vasculares,  which  are  furnished  with  spiral 
vessels.* 

We  do  not  propose  to  proceed  farther  with  the  classification  of 
plants,  however  interesting  the  natural  and  systematic  arrangement 
may  be.  It  would  occupy  too  much  space  for  the  objects  of  this 
work.  We  shall  have  occasion  to  refer  frequently  to  the  foregoing 
general  divisions,  partly  for  the  purpose  of  showing  that  they  have 
appeared  upon  the  earth  in  a  certain  period,  or  that  each  class  be- 
longs to  different  periods  of  the  earth's  history. 

33.  The  class  minerals,  which  in  its  meaning  is  co-extensive  with 
kingdom,  may  be  divided  into  orders,  and  these  orders  again  into 
genera,  and  finally  into  species.     That  there  are  large  groups  of 
minerals  which  possess  properties  in  degree  and  kind  within  cer- 
tain limits  is  no  doubt  true,  and  these  groups,  while  they  possess 
them  in  degrees  in  kind  and  quality,  also  look  alike;  that  is,  we  can- 
not fail  to  perceive  there  exists  an  outside  likeness;  we  say  outside, 
for  in  classifying  minerals  no  regard  is  paid  to  chemical  composition; 
indeed,  not  only  are  the  characters  outside  characters,  but  the  force 
which  brought  their   elements  together  are   outside   forces  also. 
Class,  in  mineralogy,  then,  circumscribes  or  comprehends  all  inor- 
ganic  bodies,    oxygen,    water,    iron,   mercury,   quartz,    mica,  &c. 
They  are  characterized  by  the  absence  of  organs.     Order  circum- 
scribes a  group  of  genera  under  one  or  more  common  characters. 
Thus  the  order  Mica  includes  those  which  are  remarkable  for  their 
easy  cleavage  in  one  direction. 

34.  The  order   Gem  includes  those  which  have  a  remarkable 
degree  of  hardness ;  the  degrees  of  which  are  limited  between  7  and 
10;  lustre  semi-metallic,  specific  gravity,  between  2.8  to  4.6.     The 
order  Baryta,  by  hardness  between  3.5  and  3.8,  and  gravity  between 
3.3  and  6.5.    This  order  embraces  soft  minerals,  but  their  specific  gra- 

*  The  division  of  stems  into  endogens  and  exogens  is  now  regarded  as  of  less 
importance  than  formerly,  as  it  is  maintained  that  the  actual  mode  of  growth  is 
much  the  same  in  both  divisions ;  still,  as  the  structure  of  these  stems  are  really 
distinguishable,  and  as  they  actually  embrace  plants  which  differ  in  other  respects, 
it  seems  to  be  important  to  the  geologist  to  keep  up  the  distinction. 


CLASSIFICATION.  39 

rity  is  high  for  earthy  bodies ;  lustre  adamantine,  in  different  degrees. 
Carbonate  and  sulphate  of  lead,  carbonate  and  sulphates  of  barytes, 
&c.,  are  examples.  Properly,  an  order  (omitting  genus)  is  repre- 
sented by  a  series  of  species,  and  their  characters,  though  of  the 
same  kind,  are  strictly  definite ;  each  species  has  its  own  degree  of 
hardness,*  its  own  specific  gravity,  its  mathematical  form  and  fixed 
dimensions,  its  color  and  its  optical  relations. 

35.  The  classification  of  inorganic  bodies  or  minerals  is  based  on 
principles  quite  different  from  those  which  we  have  just  considered. 
We  retain,  however,  as  far  as  possible  the  same  names  for  the  divi- 
sions, as  class,  family,  order,  genus,  and  species — that  is,  there  is  no 
objection  to  the  use  of  these  names  provided  there  are  divisions 
whibh  answer  to  them. 

We  also  recognise  the  same  principle  as  the  basis  of  classifica- 
tion, viz.,  resemblance.  The  resemblance,  however,  is  of  a  different 
kind  from  that  which  is  recognised  in  the  animal  and  vegetable 
kingdoms.  In  minerals  it  is  physical,  and  we  may  remark  here  that 
there  is  no  affinity  or  relationship  existing  among  inorganic  bodies. 
Classification  is  founded  on  the  resemblance  of  physical  properties, 
as  weight  or  specific  gravity,  hardness,  form,  color,  lustre.  Where 
a  group  of  bodies  possess  the  same  gravity,  the  same  hardness, 
form,  color,  and  lustre,  they  are  regarded  as  identical,  and  consti- 
tute but  one  species. 

36.  In  the  mineral  kingdom  bodies  exist  as  elements,  which  are 
undecomposed  kinds  of  matter,  and  as  compounds,  which  consist  of 
the  union  of  two  or  more  elements,  forming  thereby  a  homogene- 
ous mass.     When,  however,  such  bodies  are  aggregated  together, 
they  are  called  mixed  minerals,  as  quartz,  felspar,  and  mica,  in 
granite. 

37.  The  term  simple  is  used  in  mineralogy  in  a  sense  differing 
from  that  in  which  it  is  employed  to  express  composition  j  simple, 
in  mineralogy,  is  really  homogeneity ;  that  is,  to  the  eye  the  mass 
forms  only  one  kind  of  matter;  it  appears  to  be  simple,  but  still  is 
composed  of  two  or  more  elements,  as  carbonate  of  lime,  felspar, 
garnet,  &c. 

*  The  degrees  of  hardness  are  expressed  by  a  scale,  divided  into  ten  parts, 
beginning  with  the  softest  mineral  (talc)  known,  which  is  represented  by  hard- 
ness =  1 :  and  ending  with  the  hardest,  the  diamond  with  a  hardness  =  10. 
The  ten  selected  minerals  representing  hardness  are  talc,  salt,  calcspar,  fluorspa" 
phosphate  of  lime,  felspar,  quartz,  topaz,  sapphire,  and  diamond. 


40  MANUAL   OP   GEOLOGY. 

Another  distinction  should  be  stated.  Minerals  occur  under 
regular  geometric  forms,  or  they  are  amorphous.  The  former  are 
crystals,  bounded  by  regular  planes,  terminating  in  edges  and 
angles.  These  planes  and  angles  bear  certain  relation  to  imaginary 
lines  passing  through  the  crystal  in  the  centre  of  faces,  edges,  or 
angles,  and  which  are  called  axes.  Amorphous  minerals  have  no 
forms  which  can  be  referred  to  a  geometric  solid.  Neither  do  they 
break  in  a  manner  which  indicates  a  regular  arrangement  of  their 
particles.  In  many  amorphous  masses,  however,  a  crystalline  tend- 
ency is  often  observable,  which  shows  the  existence  of  law,  and 
that  inorganic  matter,  if  left  to  the  influence  of  its  own  primordial 
force,  would  take  or  assume  regular  forms. 

In  classification  of  the  bodies  belonging  to  the  mineral  kingdom, 
we  can  find  no  great  division  corresponding  to  branch  in  the  organic 
kingdoms.  Indeed,  there  is  strictly  but  one  class.  We  may  divide 
minerals  artificially  into  classes,  but  they  are  unnatural,  as  those  of 
Mohs's  three  classes. 

38.  Though  we  admit  that  order  is  exhibited  in  the  foregoing 
classification,  yet  we  are  unable  to  discover  in  this  class  of  bodies 
either  a  typical  or  genetic  relationship.  This  being  admitted,  it  is 
evident  that  the  systematic  arrangement  of  orders  and  species  is 
effected  on  principles  of  another  sort.  If  we  now  subject  this  classi- 
fication to  a  rigid  examination,  we  shall  be  able  to  discover  that 
species  have  position  only  in  virtue  of  their  external  aspects  and 
characters;  it  is  not  relationship  or  affinity  which  gives  them  a 
collocation  in  the  system;  for  example,  quartz,  topaz,  emerald, 
zircon,  and  beryl  are  placed  in  the  order  Gem,  for  the  reason  that 
there  is  a  physical  resemblance  among  them  which  we  cannot  dis- 
regard in  classification ;  but  it  only  gives  the  several  species  of  the 
order  a  standing  there,  because  they  possess  a  certain  degree  of 
hardness,  a  certain  kind  of  lustre,  and  a  certain  amount  of  gravity. 
To  these  physical  properties  their  position  in  the  group  is  due,  and 
not  to  relationship  of  any  kind.  A  classification  which  expresses 
position  only,  and  not  the  higher  genetic  and  typical  relations 
which  exist  in  the  organic  kingdoms,  is  a  classification  of  an  infe- 
rior kind.  It  is  a  classification,  however,  because  it  is  founded  upon 
permanent  characters  and  fixed  relations.  This  is  the  only  classifi- 
cation, too,  in  which  it  is  possible  to  arrange  bodies  in  a  linear 
series.  Minerals,  in  this  respect,  show  their  simplicity  in  contra- 


CLASSIFICATION. 


41 


distinction  to  the  complexities  of  structure  both  in  the  animal  and 
vegetable  kingdoms. 

In  conclusion,  we  remark  that  we  often  find  it  necessary  to  test 
the  value  of  the  abstract  principles  by  which  we  have  obtained  cer- 
tain results,  as  the  systems  of  classification  which  we  present  above, 
or,  in  other  words,  we  wish  to  be  satisfied  that  we  have  seized  the 
governing  characteristics  of  a  plan  or  scheme.  We  may  be  satis- 
fied with  results  when  we  find  that  thoughtful  men  have  bestowed 
proper  attention  to  characteristics,  and  they  obtain  the  same  results, 
though  they  have  pursued  different  ways.  Again,  if  a  scheme  of 
classification  is  applicable  to  the  past  as  well  as  the  present,  the 
scheme  is  worthy  of  confidence,  or  merits  belief.  If,  again,  a 
scheme  is  tested  by  two  or  more  methods,  and  they  agree  or  har- 
monize, then  we  may  regard  the  groups  as  natural,  and  that  the 
ruling  characteristics  have  been  selected  aright,  and  the  scheme  is 
founded  upon  those  general  principles  which  a  truthful  representa- 
tion requires. 

Fig.  34. 


Enripterus  remipes.    Upper  Silurian. 


CHAPTER  IV. 

GEOLOGY  DEFINED  —  ITS  OBJECTS,  ADVANTAGES  —  MEANS  BY 
WHICH  IT  IS  ACQUIRED,  AND  THE  RULES  BY  WHICH  ITS  PHENO- 
MENA ARE  INTERPRETED — SOURCES  OF  INFORMATION  POINTED 
OUT — IMPORTANCE  OF  THE  TESTIMONY  OF  ORGANIC  REMAINS — 
GEOLOGY  BASED  ON  AUTHENTIC  RECORDS — THE  THREE  PERIODS 
— ORIGIN  OF  WATER,  AND  CONTINENTAL  RIVERS  AND  SEAS. 

39.  GEOLOGY  is  a  natural  history  of  the  earth.     It  treats  of 
natural  bodies,  forces,  and  succession  of  events..    A  relation  of 
those  events,  arranged  in  the  order  in  which  they  happened,  would 
form  a  complete  history  of  the  planet  since  its  creation. 

40.  Some  of  the  objects  of  Geology  are,  to  acquire  a  knowledge 
of  the   earth's  structure,   to  discover  the   causes  which   produce 
many  of  the  phenomena  that  so  frequently  arrest  our  attention — as 
earthquakes,  volcanic  action ;  also,  those  which  have  been  instru- 
mental   in    the    accumulation    of    the    metals   near   the   surface ; 
together  with  those  which  grow  out  of  the  relation  of  the  compo- 
nent masses,  and  their  mutual  action  upon  each  other. 

41.  The.  advantages  which  flow  from  its  study  are  numerous. 
It  informs  us  where  we  may  expect  to  find  many  of  the  valuable 
productions  in  the  earth — as  iron,  copper,  gold,  silver,  mercury, 
salt,  gypsum,  coal,  and  marble ;  it  gives  us  enlarged  views  of  the 
Creator  and  his  works,  by  which  we  also  acquire  rational  views  of 
the  plan  of  creation. 

42.  It  gratifies  a  laudable  curiosity  in  reference  to  the  past,  by 
giving  us  a  more   correct  knowledge  of  what  transpired  in  the 
earliest  periods  of  the  earth's  existence.     It  shows,  from  abundant 
data,  that  the  earth  passed  through  many  important  changes  prior 
to  the  creation  of  man ;  that  plants  grew,  and  animals  lived,  upon 
the  earth  long  before  his  existence;   and  also,  that  the  changes 
and  revolutions  upon  it  were  necessary  to  prepare  it  for  his  abode 
and  that  those  changes  indicate  progressive  states  ]   that  order  has 
prevailed ;  and  that  with  respect  to  plants  and  animals,  that  they 

(42) 


GEOLOGY  DEFINED.  43 

appeared  in  the  order  of  their  rank ;  that  those  especially  which 
are  low  in  the  scale  of  organization  belonged  to  the  ancient  periods, 
while  those  which  hold  the  highest  rank  were  created  in  later 
periods,  and  just  before  the  creation  of  man. 

43.  The  means  by  which  geology  is  .cultivated,  or  a  natural  his- 
tory of  the  earth  is  acquired,  is  by  observation  and  the  application 
of   the   established   principles  of   chemistry,  mineralogy,  botany, 
zoology,  and  natural  philosophy.     Under  the  guidance  of  the  prin-' 
ciples  established  in  these  departments,  the  geologist  proceeds  to 
examine  the  relation  of  rocks  to  each  other,  to  ascertain  by  what 
agencies  they  have  been  formed,  whether  they  have  been  moved 
from  the  position  they  originally  occupied,  and  also  what  they  con- 
tain.    The  geologist  often  finds  it  necessary  to  descend  into  mines, 
ascend  mountains,  trace  out  rocks  along  watercourses  or  railroad 
cuttings,  or  visit  any  natural  or  artificial  exposure,  to  which  access 
can  be  gained. 

The  kind  of  observations  which  are  to  be  made  depends  upon 
the  object  which  we  have  in  view.  It  may  be  to  determine  the 
order  in  which  rocks  are  superimposed  upon  one  another;  or  it  may 
be  to  discover  the  existence  of  the  valuable  metals,  ores,  coal, 
marble,  salt,  &c. 

These  questions,  however,  are  too  numerous  to  be  elaborated 
in  an  elementary  treatise. 

44.  The  interpretation  of  observations  which  are  thus  made, 
must  be  in   accordance  with   established   principles,   as  we  have 
already  remarked.     For  we  may  safely  assume  that,  in  all  time,  all 
changes  and  all  phenomena  have  been  produced  by  causes  now  in 
operation.     They  may  now  operate  with  less  activity,  but  they  are 
the  same  in  kind;  so  that  we  may  safely  apply  the   established 
principles  of  modern  science  to  the  explanation  of  those  ancient 
changes,  and  have  no  occasion  to  infer  that  because  an  event  is 
remote  in  time,  it  was  the  result  of  causes  unknown  in  our  time. 
The  present  furnishes  us  with  all  the  information  required  to  make 
a  correct  interpretation.     Fire,  water,  and  atmospheric  influences, 
&c.,  have  been  the  same  throughout  all  time;  the  same  laws  have 
governed  their  effects ;  water  was  converted  into  steam,  cold  con- 
densed vapor,  fire  melted  rocks,  and  the  expansion  of  steam  and 
aeriform  bodies  rent  asunder  the  strongest  walls  in  remote  times, 
for  the  same  reasons  and  under  the  same  circumstances  as  they 
now  do. 


44  MANUAL   OP   GEOLOGY. 

45.  Our  most   authentic   information    respecting   the    earth  is 
derived  from  records  which  may  be  said  to  be  inscribed  upon  and 
within  its  strata.     These  records  consist  of  two  kinds,  the  physical 
and  organic.     To  the  first  belong  the   changes  produced  by  the 
action  of  one  portion  of  the  earth's  crust  upon  others,  which  may 
be  seen  where  its  strata  are  bent,  or  crushed,  or  moved  from  their 
former  positions ;  and  also  the  intrusions  of  rocks  in  a  melted  state 
among  those  already  consolidated,  so  that  the  latter  are  baked  and 
otherwise  changed  by  the  intruded  molten  mass. 

To  the  second  belong  the  remains  of  animals  and  plants,  which 
were  enclosed  in  the  strata  and  have  been  preserved  in  states  suffi- 
ciently perfect  in  most  instances  for  the  recognition  of  the. families 
to  which  they  belong,  and  in  other  cases  for  the  exact  determi- 
nation of  the  species. 

46.  The  testimony  of  the  remains  of  plants  and  animals  is  of  the 
utmost  importance.     They  not  only  inform  us  of  the  general  order 
which  we  have  already  mentioned,  but  especially  when  the  repre- 
sentatives of  the  different  kinds  first  began  to  exist,  as  birds  and 
mammals;  also  when  particular  species  ceased  to  exist,  and  new 
representatives  took  their  places.     From  their   distributions  and 
the  peculiarity  of  their  organization,  we  infer  the  former  condition 
and  temperature  of  the  earth. 

These  organic  records  fully  bear  out  the  conclusion,  that  the 
plan  of  organization  of  the  remotest  periods  differs  in  no  respect 
from  that  which  now  prevails,  and  there  is  no  deviation  in  structure 
from  the  four  Cuvierian  types  known  to  us  under  the  names  of 
Radiata,  Mollusca,  Articulata,  and  Vertebrata. 

47.  From  the  foregoing   statements  it  will  be  perceived  that 
geology  is  based  on  authentic  records.     It  has  established  the  law 
of  uniformity  of  action  in  the  physical  world,  and  a*  uniformity  in  the 
organization  in  the  organic  kingdoms,  which  furnishes  a  basis  for 
the  interpretation   of  both  classes  of  phenomena,  and  assures  us 
of  the  safety  and  soundness  of  applying  the  same  rules  of  reason- 
ing to  the  remote  ages  as  to  those  in  which  we  live. 

48.  In  the  preceding  paragraph,  reference   has  been  made  to 
remote  periods.    The  most  general  division  which  can  be  instituted, 
with  respect  to  our  knowledge  of  these  periods,  is  that  of  the  three 
following,  which  may  be  entitled  the  hypothetical,  the  theoretical, 
and  the  positive.     The  theoretical  may  become  positive  when  its 
theories  are  so  fully  established  as  to  be  universally  received  as  time 


OP  GEOLOGIC   FORCES.  45 

by  those  capable  of  weighing  the  proof.  The  hypothetical  is  the 
most  remote,  and  goes  back  to  a  time  when  the  matter  which  now 
composes  the  earth,  the  sun,  and  the  planets,  is  supposed  to  have 
existed  in  what  astronomers  term  a  nebulous  state,  a  state  of 
extreme  diffusion  through  an  almost  illimitable  space.  That  mat- 
ter did  so  exist,  the  proof  is  by  no  means  direct.  It  is  an  assump- 
tion, and  therefore  properly  called  an  hypothetical  state. 

The  theoretical  period  presents  certain  tangible  facts,  as  the  form 
of  the  earth  (an  oblate  spheroid),  and  the  composition  and  physical 
characters  of  its  masses;  from  which  we  may  reasonably  draw  con- 
clusions. 

The  matter  composing  the  earth  has  now  become  consolidated, 
and  during  consolidation  chemical  agencies  have  been  active  among 
As  elements,  intensely  igniting  its  mass,  and  giving  it  a  state  of 
fluidity  sufficient  to  cause  its  matter  to  accumulate  upon  its  equa- 
torial parts  by  rotation.  They  also  gave  sufficient  fluidity  to  permit 
its  particles  to  move  freely  among  themselves,  from  which  has 
resulted  the  crystalline  state  of  its  oldest  rocks. 

49.  The  third  or  positive  period,  finds  the  earth  in  a  compara- 
tively settled  condition ;  its  surface  has  cooled,  and  its  fires,  which 
had  been  lighted  by  the  powerful  affinities  of  matter,  have,  as  it 
were,  burnt  out,  and  they  exist  only  in  its  interior;   vapor  con- 
denses tipon  its  surface,  and  as  the  forces  which  have  been  gene- 
rated by  its  ignition,  have  broken  and  ridged  its  outer  envelope 
into  mountains,  the  condensed  water  flows  in  streams  and  rivers 
from  the  slopes  towards  the  great  depressions  to  which  all  con- 
verge, and  where  all  the  waters  of  a  continent  unite  and  form  the 
great  reservoirs  which  are  known  as  seas  and  oceans. 

50.  The  origin  of  water  upon  the  earth>  as  thus  explained,  seems 
to  assure  us  that  it  was  the  last  element  contributed  to  its  surface 
from  the  surrounding  space,  that  its  accession  added  an  important 
force  antagonistic  to  that  of  fire,  and  that  it  has  essentially  modified 
its  surface  by  its  mechanical  and  chemical  properties ;  in  fine,  has 
been   the  principal  agent  in   rendering  it  inhabitable  by  beings 
organized  like  man,  and  the  lower  animals. 

51.  It  may  also  be  inferred  that,  as  seas  must  have  been  formed 
by  continental  rivers   and  their  contents  have  accumulated  gra- 
dually, so  their  saline  matter  must  have  increased  slowly :  hence, 
in  the  early  existence  of  the  planet,  the  oceans  were  less  saline  than 
now — an  assumption  which  seems  to  be  sustained  by  the  absence 
of  salt  in  the  oldest  sediments,  though  they  are  all  marine. 


CHAPTER  V. 

OB  GEOLOGIC  FORCES — FIRE  AND  WATER  CONSIDERED  AS  AGENTS 
OF  CHANGE — DYNAMICS  AND  STATICS  OF  GEOLOGY. 

52.  THE  forces  which  have  been  instrumental  in  giving  form  to 
the  earth,  as  well  as  in  arranging  its  subordinate  parts,  are  two — 
Chemical  and  Mechanical.    And  the  agents  immediately  concerned 
are  also  two — -fire  and  water.    These  are,  however,  generally  spoken 
of  as  the  forces  of  geology.     The  changes  due  to  each  are  some- 
times chemical  and  sometimes  mechanical.     The  first  force  brought 
into  activity  was  fire.     It  was  generated  or  first  kindled  by  intense 
chemical  action  of  the  elements  upon  each  other,  when  their  atoms 
were  brought  together  by  condensation  from  that  highly  diffused 
state  which  we  have  referred  to  in  the  preceding  chapter.     The 
questions  which  relate  to  this  nebulous  state  of  matter,  or  hypo- 
thetical period,  belong  to  astronomy.     The  geologist,  however,  has 
occasion  to  refer  to  it  for  the  purpose  of  indicating  the  origin  of 
those  fires  whose  former  existence  seem  to  be  established  by  the 
peculiar  form  which  the  globe  has  taken — the  crystalline  state  of  all 
the  inner  deep-seated  masses,  and  by  the  actual  existence  of  fires 
within  its  crust  at  the  present  time.    This  present  heat  of  the  earth, 
we  thus  endeavor  to  trace  back  to  its  original  cause;  a  cause  cer- 
tainly adequate — regarding  it  as  the  residual  heat  of  the  cooling 
globe,  and  not  transient  heat  developed  at  uncertain  intervals  by 
the  chemical,  or  galvanic  action  of  the  materials  upon  each  other. 
Though  these  forces  undoubtedly  still  perform  important   parts, 
they  are  at  present  rather  the  results  of  this  heat  than  its  sources. 

53.  In   connection  with  the   heated   state  of   the  earth,  it  is 
necessary  also  to  consider  it  as  a  cooling  body — as  constantly  losing 
its   temperature   by  the   escape   of  its    caloric   into  space.       An 
envelope  or  crust  consequently  first  formed,  which  has  thickened 
by  the  loss  of  heat.     This  thickening  of  the  first  pellicle  formed 
must  be  beneath,   so  that  the   crystalline   covering  of  the   earth 

(46) 


OF   GEOLOGIC   FORCES.  47 

is  a  nether  formed  crust;  the  newest  portion   being  nearest    the 
centre  of  the  globe. 

54.  In  considering  the  time  required  to  form  a  cool  and  stable 
surface,  we  must  take  into  account  the  relation  of  the  rocks  to  heat, 
considering  them  as  good  or  bad  conductors,  and  also  the  fusibility 
of  different  materials  of  which  they  are  composed. 

55.  In  the  combined  effects  of  heat,  and  of  its  escape,  the  geolo- 
gist recognises  causes  which  are  competent  to  elevate  above  the 
general  level  of  the  surface,  portions  of  the  earth's  crust.     And 
probably  in  ancient  as  in  modern  periods,  these  portions  were  raised 
in  ridges,  or  formed  chains  of  mountains  similar  to  the  Alleghanies, 
Alps,  or  Andes. 

56.  The  effects  of  the  fire  force  are  also  seen  in  the  fusion  and 
heating  of  strata  wherever  exposed  to  its  action.     It  thus  vaporizes 
water,  disengages  the  gases  from  their  compounds,  and  even  vapor- 
izes sulphurets,  phosphates,  and  other  bodies  that  have   metallic 
bases. 

57.  Vapors  and  gases  being  generated,  they  must  either  escape 
through  fissures,  or,  being  confined  in  cavities,  they  exert  great 
pressure  upon  parts  already  fluid,  or  upon  the  solid  crust.    Pressure 
upon  an  incandescent  fluid  may  force  it  through  cracks  and  fissures, 
and  on   reaching  the  surface  may  flow  over  it  and  cover  strata 
already  consolidated ;  instances  of  which  are  often  witnessed  in  our 
day  in  the  overflowing  lava.     The  confined  vapors  may  also  force 
upward  the  crust,  cause  earthquakes,  and  permanently  elevate  that 
portion  immediately  above  the  place  where  they  are  confined.     But 
it  is  maintained  that  mountain  ridges  are  rather  due  to  subsidence 
of  the  strata,  by  which  the   outcropping  edge  is  tilted  up,  thus 
forming  a  ridge.     The  instances  of  change  of  level,  however,  in 
our  times  are  accompanied  by  increased  activity  of  the  fire  force,  so 
that  this  agent  is  probably  always  concerned  in  the  formation  of 
single  mountains,  if  not  all  mountain  chains.    Thus  the  Alia  Bund, 
or  Mound  of  God,  in  India,  was  raised  during  an  earthquake,  in 
1819,  ten  feet  high,  sixteen  miles  in  width,  and  fifty  miles  in 
length. 

58.  We  trace,  also,  the  origin  of  veins  and  dykes  to  igneous 
action.     The  rocks  being  rent  asunder  by  the  cooling  of  the  strata, 
or  upward  pressure  of  the  gases,  a  passage   is   opened   for   the 
water  (from  above),  holding  in  solution  various  substances  which 
may  be  deposited  upon  the  walls  of  the  fissures;  or  for  the  gases 


48  MANUAL    OF    GEOLOGY. 

and  vapors  from  beneath,  consisting  of  the  sulphurets  and  chlorides 
of  the  metals,  or  disengaged  sulphur.  The  known  laws  of  conden- 
sation of  such  bodies  upon  a  cooled  surface,  would  satisfactorily 
account  for  the  filling  of  those  rents  with  the  metals  and  their 
compounds.  The  fissures  called  dykes  were  filled  with  melted 
matter  forced  up  from  below.  Though  the  common  effect  of  fire 
is  to  elevate  the  surface  and  force  up  melted  matter,  it  sometimes 
undermines  large  areas  and  causes  a  subsidence. 

59.  The  force  of  water  is  scarcely  less  important  than  fire  in 
modifying  the  surface  of  the   earth.     It  operates  in  four  modes, 
viz. :  by  solution,  by  its  expansion  in  freezing,  by  attrition,  and  by 
transportation.     As  a  solvent,  under  common  circumstances,  it  is 
not  necessary  to  speak  of  it  particularly.    When  it  is  aided  by  heat 
or   pressure,  it  is  much  more  important.     If  aided  by  heat  and 
pressure  together,  it  dissolves  silica  and  many  other  substances,  as 
is  shown  by  the  Geysers  of  Iceland  and  the  waters  of  other  hot 
springs,  which  upon  cooling  let  fall  the  matter  that  has  been  dis- 
solved, so  that  in  the  course  of  time   large   accumulations  form 
around  the  orifice  where  the  waters  issue.     When  it  holds  carbonic 
acid  in  solution,  it  dissolves  carbonate  of  lime  and  iron,  which  it 
lets  fall  also  when  exposed  to  the  atmosphere.     The  tufa  about 
springs,  and  also  porous  oxide  of  iron,  which  are  not  uncommon 
deposits,  are  thus  formed. 

60.  When  water  freezes  it  expands  with  great  force.     Rocks  are 
thereby  rent  asunder  by  the  ice  formed  in  their  seams;  and  all 
porous   bodies,    which   absorb   water   abundantly   and    afterwards 
freeze,  are  broken  up  and  reduced  to  soil.     It  is  however  much 
more  important  as  a  mechanical  force,  when  acting  as  a  transporting 
agent.     As  it  flows  in  streams  and  rivers  from  the  mountains  to 
the  oceans,  the  debris  which  is  committed  to  it  is  carried  along  to 
these  great  basins.     It  is  estimated  that  the  Mississippi  bears  down 
sediment  enough  annually  to  form  a  stratum  one  foot  thick  and 
12  miles   square.      The  tide  wave   impinging  upon    shores,  and 
flowing  into  harbors  and  up  rivers,  transports  sediment  during  its 
ebb,  and  as  it  pursues  outward  its  course,  deposits  it'  at  all  points 
where  its  force  is  diminished  by  obstructions.     A  bar  is  formed 
where  it  meets  river  currents,  and  hence  the  navigation  of  rivers 
is  often  obstructed.     The  Atlantic  tidal  wave  is  both  constructive 
and  destructive.     It  is  more  destructive  when  its  force  is  aided 
by  winds.     The  waves  which  break  upon  the  shores  cast  up  sand, 


OP   GEOLOGIC   FORCES.  49 

a  part;  of  which  is  often  blown  inland,  making  desert  and  sterile 
large  areas  which  lie  in  the  course  of  the  prevailing  wind.  Another 
portion  of  the  land  is  often  raised  into  a  ridge  nearly  parallel  with 
the  shore  line.  Such  ridges  often  form  along  the  shore  of  inland 
lakes,  and  have  been  mistaken  for  moraines. 

61.  The  great  ocean  river,  known  as  the  Gulf  Stream,  is  a  still 
more  important  flow  of  water.     It  is  a  bearer  of  both  heat  and 
sediment. 

That  portion  of  the  great  equatorial  current  between  Africa  and 
America,  impinges  upon  Cape  St.  Roque,  in  Brazil;  then  flows 
onward  into  the  Mexican  Gulf,  where  it  is  heated  to  88°  F. ;  then 
passing  out  by  the  Florida  Keys,  it  flows  N.  E.,  and  finally  approxi- 
mates the  north-western  coast  of  Europe.  It  parts  with  its  heat, 
which  is  distributed  by  the  prevailing  westerly  winds  over  the 
western  and  north-western  coast  of  the  Continent.  During  its 
progress  the  fine  sediment  it  received  from  the  Amazon  and  Mis- 
sissippi, is  distributed  along  its  course  upon  the  ocean's  bottom. 

62.  The  vastness  of  the  scale  upon  which  water  operates,  is  indi- 
cated by  the  extent  of  ocean  surface.     Thus,  the  Atlantic  has  an 
area  of  25,000,000  of  miles;  the  Pacific  70,000,000;  while  the 
earth  has  only  35,000,000.    Fig.  42. 

63.  From  the  foregoing  statements,  we  may  perceive  that  the 
sediments  which  are  transported  by  water  to  the  ocean  are  the 
materials  of  a  large  class  of  rocks,  which  it  is  evident  may  be 
recognised  by  the  earthy  character  which  they  must  assume,  and 
the  intermingling  of  such  debris  with  various  kinds  of  organic 
matter.     Water  in  the  act  of  transporting  the  debris  of  rocks, 
whether  fine  or  coarse,  must  necessarily  bring  this  matter  into  col- 
lision with  rocks  and  with  its  own  moving  particles :  hence,  most 
matter  thus  transported  bears  evidence  of  the  attrition  to  which  it 
has  been  subjected;  and  the  rocks  bear  external  evidence  of  their 
origin,  though  the  limestones,  which  seem  to  have  been,  in  part  at 
least,  in  chemical  solution,  are  frequently  crystalline,  and  in  this 
condition    their   sedimentary   character   may   be    disguised.     The 
winds    are   important    agents    in    producing   geological   changes. 
Evaporation  goes  on  continually.     From  oceans,  seas,  rivers,  lakes, 
and  the  surface  of  the  earth,  vapors  of  water  are  ever  rising,  borne 
by  winds  over  the  highlands  and  mountains  of  continents ;   it  is 
there  condensed,  and  falls  in  the  form  of  rain,  or  snow,  affording  a 
never-failing  supply  of  water  for  mountain  streams  and  continental 

5 


50  MANUAL   OF   GEOLOGY. 

rivers,  to  flow  on  back  to  the  oceans  and  large  bodies  of  water,  and 
to  rise  again  in  the  form  of  vapor.  Great  changes  are  effected  by 
this  circulation  and  interchange.  Slowly,  but  surely,  the  hardest 
rocks  are  worn  down  and  softened ;  the  surface  of  the  whole  earth 
is  modified ;  debris  from  the  mountains  and  hills  is  carried  down 
and  spread  out  over  the  plains,  or  the  c  *<ean  beds. 

64.  We  may  observe  in  closing  our  remarks  relative  to  geologic 
forces,  that  they  are  often  alluded  to  as  the  Dynamics,  of  Geology, 
a  phrase  which  is  employed  to  express  in  the  aggregate  all  the 
forces  which  have  been  in  any  way  productive  of  change  in  and 
upon  the  earth's  crust,  whether  fire  or  water,  molecular  force,  the 
assorting  power  of  water,  or  chemical  action. 

65.  The  Statics  of  Geology  is  another  phrase  equally  comprehensive. 
It  is  designed  to  express  the  condition  of  the  rocks  and  of  the  sur- 
face as  they  are,  without  regard  to  cause.     Statical  geology,  how- 
ever, stands  first  in  the  order  of  investigation,  or  of  time.     It  is 
necessary  to  observe  and  weigh  all  the  facts  respecting  the  statics, 
before  we  are  in  a  condition  to  determine  questions  relative  to  their 
dynamics.     The  dynamics  should  always  grow  out  of  the  statics 
of  geology.     When  the  statics  have  been  fully  investigated,  the 
deductions  of  geology  are  placed  upon  as  sound  a  basis  as  those 
which  belong  to   astronomy.     Or  when  our  conclusions   are  thus 
guarded   and  eliminated  of  suspected    error,  the    earth's    history 
becomes  as  truthful  and  as  worthy  of  belief  as  the  history  of  the 
ancient  nations,  Greece  and  Rome. 

Fig.  35. 


Disintegration  of  granite,  resulting  in  the  form  called  tors  or  cheese  rings. 


CHAPTER  VI. 

CLASSIFICATION   AND    NOMENCLATURE   OP   BOCKS. 

66.  THE  principle  upon  which  a  classification  of  rocks  should  be 
based  is  no  doubt  that  which  recognises  in  its  scheme  those  facts 
which  express  the  mutual  relation  of  all  the  masses  composing  the 
earth's  crust.  This  principle  is  probably  the  true  one,  because  it 
expresses  the  historical  idea,  which  in  geology  is  always  the  promi- 
nent one,  and  the  one  which  requires  the  fullest  elucidation.  This 
principle,  however,  has  not  been  employed  in  classification  except- 
ing in  a  very  general  sense.  In  the  older  classifications  attempts 
were  made  to  sub-divide  rocks  upon  this  principle ;  thus,  the  three- 
fold division  into  primary,  secondary,  and  tertiary  expresses  this 
relation.  A  more  recent  threefold  division  is  indicated  by  the  use 
of  terms  which  express  remotely  the  sequence  of  formations  accord- 
ing to  the  antiquity  of  their  organic  remains,  and  they  are  tolerably 
well  expressed  by  the  terms  Palaeozoic,  Mesozoic,  and  Cainozoic; 
terms  which  have  reference  to  the  relative  age  of  the  fossils  which 
are  contained  in  the  rocks. 

While  then,  the  classification  of  rocks  is  based  upon  the  time  or 
period  when  they  were  formed  or  deposited,  the  nomenclature  is  not 
fortunate,  as  there  is  generally  a  want  of  meaning  in  the  names 
which  correspond  to  the  historical  idea.  The  rocks,  or  groups  of 
rocks,  fall,  it  is  true,  into  an  historical  arrangement,  but  the  nomen- 
clature fails  to  express  it  except  in  the  most  general  way ;  and  pro- 
bably in  the  present  state  of  the  science  it  is  not  possible  to  change 
it  materially,  or  even  so  far  as  to  bring  about  a  reconciliation  of  the 
historical  arrangement  with  the  names  employed  to  express  it. 
Hence  it  will  be  observed  that  certain  names  which  are  employed 
for  the  groups  or  systems,  are  derived  from  localities  or  places  where 
the  particular  rocks,  groups,  or  systems  are  supposed  to  be  displayed 
to  the  best  advantage  for  study.  Thus  the  terms  Silurian,  Devonian, 
and  Permian  indicate  localities.  Other  names  express  merely  a 

(51) 


52  MANUAL   OF   GEOLOGY. 

fact  indicative  of  the  lithological  composition,  as  Quartz  Rock,  Calci- 
ferous  Sandstone,  Cretaceous  System  :  or  in  other  cases,  the  mineral 
contents,  as  Carboniferous :  in  others  still,  the  names  are  derived 
from  the  structure  of  the  masses,  as  Lias  and  Oolite :  and  lastly, 
names  are  employed  which  express  the  relations  of  past  periods  to 
the  present:  as  Eocene,  Miocene,  and  Pliocene.  In  this  country 
it  has  been  customary  to  adopt  the  European  names  of  classes,  and 
apply  them  to  our  larger  divisions  or  their  equivalents.  Thus  in 
New  York,  it  turns  out  that  the  rocks  which  prevail  over  the 
greater  part  of  the  state  may  be  referred  to  the  systems  which  in 
England  have  been  called  Silurian  and  Devonian ;  accordingly, 
we  speak  of  the  Silurian  and  Devonian  systems  in  this  country  in 
the  same  manner  as  geologists  of  England,  though  we  have  neither 
a  Siluria  nor  a  Devonshire.  But  while  we  thus  adopt  the  general 
European  names  for  our  systems,  we  have  applied  American  local 
ones  to  our  groups  or  subordinate  divisions.  These  names  have 
been  generally  selected  from  the  places  where  the  groups  may  be 
studied  to  the  best  advantage;  for  example,  the  Potsdam  sand- 
stone, Champlain  group  or  division,  Onoudaga  limestone,  Niagara 
group,  &c.,  are  names  applied  according  to  the  principle  stated. 
The  term  series  is  often  employed  in  place  of  the  word  group. 
In  either  case  the  words  indicate  that  there  are  several  beds  or  rocks 
which  are  closely  connected  together,  or  so  closely  related  by  their 
fossils,  that  they  belong  to  one  epoch. 

67.  The  most  general  divisions  which  are  now  adopted  in  this  coun- 
try are  based  upon  the  nature  of  the  forces  which  have  been  instru- 
mental in  their  formation.  These  divisions  are  recognisable  by  the 
phenomena  peculiar  to  their  operation  and  effects.  Fire  produces 
effects  which  need  not  be  mistaken ;  variable  it  is  true,  according 
to  conditions,  but  recognisable  still,  though  extremely  different. 
In  one  case  fire  gives  us  perfect  crystals,  or  a  crystalline  mass,  as 
in  granite ;  but  lava,  which  is  a  molten  rock,  is  an  amorphous  slag 
or  a  glass,  which  being  cooled  suddenly  in  the  air,  its  particles  had 
no  time  to  arrange  themselves  symmetrically ;  thus  conditions  deter- 
mine the  results. 

Rocks  which  are  crystalline  by  the  influence  of  this  agent  are 
properly  called  Pyro-crystaUine ;  crystallized  by  fire.  It  may  be 
assumed  that  at  one  period  the  entire  crust  was  acted  upon  by  fire. 
Its  exposure,  however,  in  space  to  a  cold  medium,  abstracted  the 
heat,  until,  in  process  of  time,  it  was  reduced  to  that  temperature 


CLASSIFICATION   AND   NOMENCLATURE   OF   ROCKS.  53 

which  was  required  to  condense  the  surrounding  vapors.  The 
deposition  of  water  was  the  result  j  and  it  speedily  became  itself  an 
agent  of  great  force  and  power.  This  agent  became,  too,  the  parent 
of  a  new  class  of  rocks ;  these  were  formed  mainly  by  its  mecha- 
nical action,  or  by  abrasion  of  the  consolidated  crust.  From  the 
nature  of  its  action  and  the  insolubility  of  the  materials  thus  pro- 
duced, their  consolidation  would  result  in  the  formation  of  amor- 
phous beds,  or  strata,  superimposed  upon  one  another.  The  move- 
ment of  the  waters  would  mould  these  materials  as  they  gradually 
accumulated,  and  hence  this  class  of  rocks  has  been  appropriately 
named  hydroplastic,  moulded  by  water,  or,  in  consequence  of  their 
being  formed  of  particles  deposited  in  this  medium,  they  are  fre- 
quently called  sediments,  or  sedimentary  rocks.  But  water  under 
favorable  conditions  dissolves  the  materials  which  are  in  contact  with 
it,  and  hence  such  rocks  do  not  appear  like  the  mechanical  sedi- 
ments ;  they  are  even  crystallized :  this  is  particularly  the  case  with 
the  limestones. 

As  the  phenomena  of  fire  are  due  to  its  variable  action,  accord- 
ing to  the  condition  of  the  body  when  cooling,  and  the  length  of 
time  its  heat  is  escaping,  it  is  necessary  to  recognise  another 
class  or  division  of  rocks;  those  for  example  which  are  cooled 
under  great  pressure,  having  been  ejected  from  fissures  and  flowed 
over  masses  already  consolidated;  and  those  masses  which  are 
ejected  from  a  crater  into  the  open  air,  all  such  rocks  may  be  called 
J^weowsorPyro-plastic  rocks.  These  are  massive,  though  crystalline 
particles  may  be  disseminated  through  them.  They  are  found  in 
thick  beds  reposing  upon  those  which  are  sedimentary  or  pyro-crys- 
talline ,  or  they  fill  ancient  rents,  formed  in  consequence  of  the  cool- 
ing of  the  earth's  crust.  The  term  primary  has  been  very  gene- 
rally applied  to  the  first  of  the  foregoing  divisions  or  classes ;  but 
as  some  of  the  pyro-crystalline  rocks,  as  the  granites,  have  been 
formed  in  all  periods,  the  term  is  therefore  loosely  applied ;  indeed 
all  the  members  which  make  up  these  divisions  belong  to  all  periods, 
and  hence  the  names  employed  are  general,  and  express  merely  the 
nature  of  the  agent  to  which  they  are  due. 

68.  The  Hydro-plastic  rocks,  or  those  due  to  action  of  water,  have 
been  subdivided  into  three  divisions.  The  names  applied  to  these 
divisions  express  the  relative  antiquity  of  their  organic  remains,  as 
the  Palaeozoic,  the  ancient  forms  of  life  ;  the  Mesozoic,  the  middle 
forms,  and  the  Cainozoic,  the  recent  forms  of  life,  or  which  most 
5* 


54 


MANUAL   OP   GEOLOGY. 


CAINOZOJC. 


resemble  those  belonging  to  our  pwn  period.  The  term  primary, 
it  should  be  observed,  is  sometimes  applied  to  the  palaeozoic  rocks , 
it  then  has  reference  to  the  organic  beings  which  they  enclose. 
They  are  primary,  as  they  were  created  first,  or  have  preceded  many 
other  organic  beings  in  time. 

69.  The  three  foregoing  divisions,  however,  are  not  of  equal 
length.  The  oldest,  or  palaeozoic,  is  by  far  the  most  protracted 
period,  the  cainozoic  is  comparatively  short.  The  annexed  diagram 
expresses  the  relative  length  of  these  periods 

While,  however,  the  inequality  of  these 
periods  is  a  well  established  fact,  there  are  rea- 
sons for  their  adoption.  In  the  first,  or  cainozoic, 
the  organic  remains  as  a  whole  are  closely  related 
to  those  now  living,  and  besides  in  the  oldest 
beds  a  few  species  are  identical  with  those  which 
still  exist. 

On  the  contrary,  there  are  no  living  species 
in  the  mesozoic  period,  and  their  general  cha- 
racteristics are  more  remote  from  those  of  the 
living,  than  those  belonging  to  the  first  or  fore- 
going division.  The  organic  remains  of  the 
palaeozoic  division  resemble  still  less  the  animals 
and  plants  with  which  we  are  familiar,  and  most 
of  its  genera  are  extinct;  and  hence  is  in  reality 
the  period  of  ancient  life  as  its  name  expresses. 


MESOZOIC 


PALAEOZOIC. 


The  progress  of  discovery  may  change  somewhat  the  relations  of 
these  periods,  but  will  not  probably  remove  the  foundation  upon 
which  they  are  based. 

70.  The  foregoing  divisions  are  subdivided  into  systems.     These 
subdivisions  are  intended  to  be  founded  upon  the  intimate  relations 
which  their  organic  remains  hold  to  each  other.     The  beginning 
and  outgoing  of  a  system  are  marked  by  physical  changes.     The 
condition  of  the  sediments  indicates  changes  in  the  earth's  crust, 
and  a  violent  movement  of  the  waters ;  hence  beds  of  coarse  and 
fine  pebbles,  or  conglomerates,  constitute  the  physical  boundaries 
of  systems,  and  a  change  in  the  organic  contents  more  or  less 
extensive  appears  in  the  fauna  preserved  in  the  adjacent  systems. 

71.  The  beginning  of  a  system  is  usually  marked  by  the  appear- 
ance of  certain  important  fossils,  which  are  also  confined  or  limited  to 
its  special  range.    A  system  then  is  represented  by  a  series  of  rocks 


CLASSIFICATION   AND   NOMENCLATURE   OF  KOCKS. 


CAINOZOIC. 

Pleistocene. 
Pliocene. 
Miocene. 
Eocene. 


which  contains  fossils   peculiar   to  it,   and   they  are  collectively 
regarded  as  representing  a  particular  era. 

The  order  of  the  systems  is  represented  in  the  annexed  geological 
column.  . 

Each  general  division  includes  seve- 
ral subordinate  systems.  It  is  conve- 
nient also  to  subdivide  the  systems 
into  upper,  middle,  and  lower,  as  the 
upper,  middle,  and  lower  sections  of 
the  Silurian  or  Devonian  Systems,  as 
it  enables  the  geologist  to  particularize 
the  fossils  characteristic  of  each  sec- 
tion, if  necessary,  or  if  they  admit 
of  it. 

The  Pyro-plastic  System  is  often  in- 
tercalated irregularly  with  all  the  sys- 
tems, as  intruded  igneous  masses.  It 
is  of  all  ages.  It  has  no  constant 
position,  yet  there  are  certain  epochs 
in  which  the  traps  and  porphyries  were 
ejected  in  greater  force  than  in  others. 
These  seem  to  have  been  eras  of  great 
disturbance,  and  are  characterized  by 
outbursts  of  molten  matter. 


MESOZOIC. 
Cretaceous. 
Jurassic. 
Triassic. 


PALAEOZOIC. 
Permian. 
Carboniferous. 
Devonian. 
Silurian. 
Taconic. 


Laminated  or  Gneiss  Sys- 
tem, Massive  Pyro-crystal- 
line  System,  Granites,  &c. 


Fig.  36. 


Unconformity  of  the  Lower  Silurian  with  the  Gneiss  at  Montmorency,  Canada  East. 
e,  d,  c,  b.  Lower  Silurian,    a.  Gneiss.   /.  Black  Slate. 


56 


MANUAL   OF   GEOLOGY. 


72.   Table  of  Formations  and  Stages  according  to  U  Orbigny. 


FOKMATIONS.                                  STAGES. 

Total  number  of 

species  of  animals 

Contemporaneous.      28.  Contemporaneous 

With   the   pre-      known  to  D'Orbig. 
ny  in  1850  in  the 

sent  epoch. 

formations. 

No.  of  Mollusks  in 

the  Stages. 

"27.  Subapennine. 

444 

26.  Falunian. 

2903 

Tertiary. 

25.  Parisian. 

1478 

6,040 

24.  Swessonian. 

562 

r23.  Danian. 

47 

22.  Senonian. 

1061 

21.  Turonian. 

218 

Cretaceous. 

20.  Cenomian. 

627 

4,098 

19.  Albian. 

307 

18.  Aptian. 

146 

17.  Neocomian. 

656          j 

16.  Portlandian. 

59          : 

15.  Kimmeridgian. 

184 

14.  Corallian. 

403 

13.  Oxfordian. 

499 

Jurassic. 

12.  Callovian. 
11.  Bathonian. 

253 

407 

3,785 

10.  Bajocian. 

508 

9.  Toarcian. 

273 

8.  Liasian. 

270 

.    7.  Sinemurian. 

163 

Triassic.         /   6'  Saliferian- 
I    5.  Conchylian. 

IM          1           84° 

4.  Permian. 

82          -] 

3.  Carboniferian. 

887 

2.  Devonian. 

1054 

Palaeozoic. 

1.  Silurian  :  — 
Upper  Silurian, 

or 

3,184 

Murchisonian 

356 

Lower  Silurian, 

or 

Silurian  Proper.     375          J 

14,947 


17,947 


CHAPTER  VII. 

CLASSIFICATION  OF  THE  PYRO-CRYSTALLINE  ROCKS — AGE  OP 
GRANITE  AND  ITS  ASSOCIATES — SUCCESSIVE  FORMATION  OF 
GRANITE  AND  ITS  DISTRIBUTION — INDIVIDUAL  ROCKS  DE- 
SCRIBED, ETC. 

73.  THE  classification  of  rocks  is  in  part  based  upon  the  forces  or 
agents  which  have  been  described.     There  are  strictly  only  two 
classes :  first,  embraces  those  whose  structure  and  position  clearly 
prove  that  they  have  been  melted  or  partially  fused.     These  have 
been  named   igneous,  or  Pyro-crystalline   rocks.      Second,   those 
which  are  evidently  Sediments,  or  have  been  deposited  from  water : 
they  have  been  called  sedimentary,  Hydro-plastic,  and  often  termed 
Stratified  rocks.     The  first  class  is  subdivided  into  three  systems  : 
the  Massive  Pyro-crystalline,  the  Laminated  Pyro-crystalline,  and 
the  Pyro-plastic  rocks.     The  first  system  embraces  granite  and  gra- 
nitoid rocks,  among  which  we  may  rank  Syenite,  Hypersthene  rock, 
and  Pyro-crystalline  limestone,  with  their  subordinates,  the  Magnetic 
and  Specular  ores  of  iron,  Serpentine  and  Rensselaerite.* 

74.  Granite.     Common  Granite  is  composed  of  three  elements  : 
Quartz,  Feldspar,  and  Mica.     These  elements  are  variable  in  size 
and  proportions.     They  may  be  very  coarse  or  fine,  or  any  inter- 
mediate degree  of  coarseness.     Each  of  the  constituents  may  in 
different  localities  predominate  over  the  others,  and  produce  vari- 
eties of  granite.     The  feldspar  may  predominate  and  hornblende 
take  the  place  of  the  mica ;  this  composition  is  called  Syenite.    The 
color  is  gray,  flesh-color,  or  quite  red.     The  feldspar  imparts  the 
color :  the  quartz  is  invariably  gray. 

The   feldspar,  mica,  and  hornblende   are  crystallized,  but  the 
quartz  never,  and  is  frequently  impressed  both  by  the  mica  and 

*  We  do  not  recognise  metamorphism    as  a  suitable  characteristic  upon  which 
to  base  a  classification,  as  any  rock  may  be  metamorphic. 

(57) 


58 


MANUAL   OF   GEOLOGY 


feldspar,  which  seems  to  indicate  that  the  feldspar  and  mica  cooled 
and  crystallized,  while  the  quartz  continued  plastic.* 

75.  Granite  and  other  pyro-crystallme  rocks  separate  into  angular 
blocks  after  long  exposure  to  atmospheric  influences.  It  is  un- 
doubtedly due  to  crystallization  of  the  mass.  There  is  also  a  separa- 
tion into  beds,  which  resemble  the  thick  beds  of  sediments.  Several 
may  be  observed  parallel  with  each  other.  They  are  not  due,  how- 
ever, to  stratification,  as  they  are  always  parallel  to  the  slope  of  the 
surface  where  they  occur.  Fig.  37  shows  the  structure  of  granite 

Fig.  37. 


. 

Structure  of  Granite. 

and  granitoid  rocks,  as  it  is  nearly  uniform  in  the  whole  class. 
The  first  appearance  of  the  division  of  the  mass  is  merely  in* 
lines;  subsequently,  disintegration  takes  place  along  those  lines, 
and  the  blocks  are  finally  separated.  The  fine  or  middling  granites 
occur  in  beds  extending  over  large  areas,  but  the  white  and  coarsest 
kinds  are  limited,  and  are  usually  in  veins  in  other  rocks,  particu- 
larly in  mica  and  talcose  slates  and  gneiss.  The  white  coarser 
granites  are  most  frequently  the  repositories  of  other  minerals,  as 
tourmaline,  beryl,  quartz  crystals,  large  plates  of  rnica,  spodumene, 
&c.  Tin  is  supposed  to  belong  to  the  syenitic  granites,  though  it 
occurs  in  small  crystals,  in  the  coarse  granite  of  Chesterfield  and 
Gosh  en  mass. 

76.  Aye  of  Granite  and  its  associates. — Granite  forms  the  high- 


*  Quartz  is  much  more  refractory  in  the  fire  than  feldspar  or  mica;  but  quartz 
undoubtedly  retains  its  fluidity  after  these  have  been  consolidated,  or  is  longer  in 
cooling. 


CLASSIFICATION    OF   THE   PYRO-CRYSTALL1NE   ROCKS.         59 

esfc  peaks  of  mountains,  and  may  be  regarded  as  among  the  highest 
rocks  geographically,  and  is  also  known  as  the  lowest  or  to  exist 
beneath  all  others,  and  hence  is  probably  the  oldest ;  yet  it  is  in- 
truded among  all  the  later  rocks  down  to  the  time  of  the  deposition 
of  the  chalk.  We  may  therefore  speak  of  the  newer  and  older 
granites,  inasmuch  as  they  appear  to  have  been  formed  during  all 
periods  of  the  earth's  history  down  to  the  chalk.  Its  relative  age, 
therefore,  is  determined  only  from  the  rocks  with  which  it  is  asso- 
ciated. 

Many  localities  in  Massachusetts  show  masses  of  granite  reposing 
upon  the  nearly  vertical  lamina  of  mica  slate. 

77.  The  oldest  granite  appears  upon  and  forms  the  highest  moun- 
tain peaks.  These,  on  cooling,  became  fissured  and  cracked,  through 
which  newer  granites  were  ejected.  Fig.  38  illustrates  the  succes- 

Fig.  38. 


Successive  Formations  of  Granite. 


sive  formations  of  granite  cooled  from  above  downward,  the  late* 
*beds  sending  veins  into  the  older,  which  are  above  them.  The  dia- 
gram also  represents  the  order  in  which  the  hypogenic  rocks  may  be 
formed.  The  granites  may  therefore  increase  in  thickness  by  acces- 
sion of  matter  both  from  above  and  below. 

78.  Distribution  of  Granite. — The  coarse  varieties  of  granite 
occur  in  Chester,  Russel,  Norwich,  Chesterfield,  and  Goshen,  Massa- 
chusetts. Paris,  in  Maine.  Fine  granites  have  long  been  known 
and  quarried  for  building  in  Quincy,  Chelmsford,  Fitchburgh,  and 
Sharon.  In  Maine  at  Hallowell,  and  other  places,  the  same  fine 
beautiful  varieties  occur.  These  varieties  hold  remarkable  relations 
to  other  rocks.  They  overlie  and  rest  upon  them.  The  matter 
composing  these  beds  issued  from  fissures  in  the  rocks  upon  which 
they  rest  and  overflowed  large  surfaces.  Near  Augusta  and  Hal- 
lowell, Maine,  in  Warren  County,  North  Carolina,  this  kind  of  gra- 
nite may  be  seen  reposing  upon  the  highly  inclined  lamina  of  mica, 


60  MANUAL   OF   GEOLOGY. 

slate,  gneiss,  and  hornblende.  In  the  Southern  States  the  first  or 
most  easterly  range  of  granite  appears  on  a  belt  separating  the  low 
country  from  the  upper,  as  at  Richmond,  Va.,  Weldon,  Rocky- 
mount,  and  vicinity  of  Buckhorn  in  North  Carolina. 

79.  TheHoosick  and  Green  Mountain  range,  the  Blue  Ridge  pass- 
ing through  the  Middle,  Southern,  and  South-Western  States,  furnish 
many  localities  of  granite.     In  Caldwell  and  Wilkes  counties  in  N. 
C.,  heavy  beds  of  porphyritic  granite  flank  the  Blue  Ridge  on  the 
eastern  slope,  and  occupy  a  part  of  the  upper  valley  of  the  Yadkin. 
They  are  rarely  the  depositories  of  valuable  minerals. 

80.  Hypersthene  Rock. — This  rock  has  the  common  structure 
and  appearance  of  granite,  but  contains  less  mica  and  quartz ;  in- 
deed it  is  composed  mainly  of  Labradorite,  and  a  small  quantity  of 
Hypersthene.     In  the  fine  grained  varieties  large  crystalline  masses 
are  imbedded,  which  gives  it  a  resemblance  to  porphyritic  granite. 
Its  colors  are  variable ;  light  gray,  passing  into  dark  smoke  gray. 
The  Labradorite  is  blue  and  bronze  or  yellowish,  and  takes  a  fine 
polish,  and   is  beautiful   for  ornaments.     There  are  several  com- 
pounds worthy  of  notice.     Labradorite  and  hornblende,  hornblende 
and  epidote,  granular    Labradorite    and   mica,  with  disseminated 
grains  of  magnetic  iron. 

Distribution. — It  is  confined  mostly  to  the  Adirondack  Mountains 
of  New  York,  and  contains  large  beds  of  magnetic  iron  ore. 

81.  Py ro-crystaUine  Limestone. — This  rock  has  the  structure  of 
granite,  and  often  has  a  granitoid  appearance.    It  is  massive  and  like* 
granite,  and  divides  into  angular  blocks,  and,  as  it  is  usually  associated 
with  the  older  rocks,  its  age  is  not  determinable  except  relatively. 
It  has  been  mistaken  for  a  Silurian  limestone,  but  at  several  locali- 
ties  in  northern  New  York  the  Potsdam  sandstone  rests  upon  it. 
So,  also,  it  is  found  evidently  ejected  from  fissures  in  the  hyper- 
sthene  rock,  in  which  case  it  is  an  igneous  rock,  resembling  in 
structure  the  coarse  granites  of  New  England.     So,  also,  it  occurs 
in  distinct  veins  or  dykes ;  hence  it  is  necessary  to  describe  it  as  a 
pyro-crystalline  rock.     Its  relation  to  granite  is  shown  from  a  local- 
ity in  Chesterfield,  Essex  County,  N.  Y.,  where  it  underlies  granite. 
Many  others  might  be  cited.     It  also  occurs  in  veins  near  Rossie, 
St.  Lawrence  County,  New  York.       It  protrudes  through  hyper- 
sthene  rock  at  Long  Pond,  Essex  Co.,  as  represented  at  a  (fig.  39). 
Its  relation  to  the  Potsdam  and  calciferous  sandstones   at  Moriah, 
Essex  Co.,  where  it  is  associated  with  hornblende  and  gneiss,  proves 


PYRO-CRYSTALLINE   ROCKS. 


61 


Fig.  39. 


that  it  is  not  an  altered  Silurian  rock, 
as  the  former  rest  a'gainst  the  latter. 
Fig.  40  a,  Potsdam  and  calciterous  sand- 
stone :  1-1,  hornblende;  2-2,  pyro-crys- 
talline  limestone;  3-3,  gneiss.  It  is 
evidently  an  intruded  rock.  Other 
rocks  occur  in  isolated  masses  in  this 
limestone.  Fig.  41  represents  an  in- 
stance occurring  near  Port  Henry, 
Essex  Co.,  N.  Y.  :  a,  limestone  ;  b, 
hornblende. 

Compounds  of 
limestone  and  ser- 
pentine are  com- 
mon in  Northern 
New  York,  in  Es- 
sex  and  Warren 
Co.    It  forms  the 
ophicalce  of  Brog- 
niart.      Its   rela- 
tions    to    other! 
rocks  do  not  differ 
from  the  pure  unmixed  limestone. 
It  may  be  polished  when  it  forms 
,  the  serpentine  marbles,  which  are 
quite  ornamental  for  parlor  tables 
and  mantel  pieces. 

82.  Localities   and   Distribu- 
tion. —  The  massive   kinds  occur 
in  St.  Lawrence,  Essex,  and  War- 
ren counties  of  New  York,  also 

in  the  highlands  of  the  Hudson  Kiver,  and  in  Sparta  and  Sterling 
in  New  Jersey,  and  other  places. 

This  rock  is  rich  in  minerals.  Of  the  metallic  oxides  it  contains 
iron,  zinc,  franklinite,  and  sphene.  Of  the  order  Gem,  blue  and 
red  corundum,  spinelle,  zircon,  brown  tourmaline,  and  quartz.  Of 
the  order  Haloide,  phosphate  of  lime,  calcspar,  mica,  and  graphite 
are  also  common  in  this  rock  :  the  latter  seems  to  be  a  characteristic 
mineral. 

83.  Serpentine.  —  This  rock  is   unlike   granite,  as   it  is  always 
6 


Moriah  Section. 


Fig.  41. 


Isolation  of  other  Rocks  in  Limestone. 


62  MANUAL   OF   GEOLOGY. 

homogeneous  and  has  a  fine  grain.  Its  predominant  color  is  green, 
but  it  is  also  brown,  yellowish  brown,  and  black.  A  mountain  mass 
is  always  divided  into  wedge-form  fragments,  never  cubical  or  in 
regular  blocks.  The  question  respecting  the  origin  of  this  rock  is 
an  interesting  one.  While  we  have  some  doubts  of  its  igneous  ori- 
gin, that  view,  upon  the  whole,  is  better  sustained  than  any  other. 
While  we  would  not  rank  it  positively  in  the  pyro-crystalline  sys- 
tem, we  can  scarcely  doubt  that  heat  has  had  much  to  do  with  its 
formation.  It  seems  to  be  closely  related  to  the  trappean  or  the 
pyro-plastic  rocks.  The  existence  of  silicious  layers  and  lamina 
often  drusy,  together  with  calcedony  and  minerals  of  this  order, 
indicate  that  serpentine  may  have  had  an  intimate  relation  to 
ancient  hot  springs. 

84.  It  occurs  in  the  midst  of  other  rocks  in  a  manner  similar  to 
those  which  are  known  to  be  intruded  or  eruptive  ones.     Serpen- 
tine veins  are  rare ;  and  it  is  also  rarely  a  metamorphic  rock,  as  at 
Syracuse  in  New  York. 

The  minerals  contained  in  serpentine  are  the  ores  of  chrome  and 
magnetic  iron.  The  latter  exists  in  a  large  vein  at  Troy,  Vt. :  it  is 
also  disseminated  through  the  rock  at  Middlefield,  Mass.  Lead  ores 
occur  in  it  in  North  Carolina.  Diallage  and  schiller  spar  are 
its  most  common  earthly  minerals.  Native  gold  has  also  been 
found  in  quartz  veins  in  this  rock. 

85.  Distribution. — It   occurs   at  New  Fane,  Vt. ;    Middlefield, 
Chester,  &c.,  in    Massachusetts*.     It  is  common  along  the  entire 
range  of  the  Alleghanies  in   Pennsylvania,  Delaware,  Maryland, 
Virginia,  North  Carolina,  &c. 

Rensselaerite. — This  rock  resembles  a  compact  serpentine ;  it  is 
greenish,  gray,  and  sometimes  black.  Its  hardness  is  about  equal 
to  fluor  spar.  It  is  homogeneous.  It  is  composed  of  silica,  mag- 
nesia, lime,  oxide  of  iron,  and  water.  It  seems  to  belong  to  the 
intruded  or  eruptive  rocks.  It  occurs  in  large  beds  at  Russel,  St. 
Lawrence  Co.,  N.  Y. 

86.  Magnetic  Oxide  of  Iron,  or  Octahedral  and  RJiombohedral 
Iron  RocJc. — Octahedral  iron  rock  occupies   a  large   area  in  the 
Adirondack  Mountains  in  Northern  New  York.     It  has  a  structure 
quite  similar  to  the  hypersthene  rock  in  which  it  occurs. 

The  Rhombohedral  iron  rock  is  less  extensive,  but  is  sufficiently 
so  to  merit  a  place  among  the  constituent  masses  of  the  globe.  It 


PYRO-CRYSTALLINE  ROCKS. 


63 


is   associated  with  the  serpentines  and  pyro-crystalline   limestone 
of  St.  Lawrence  Co.,  N.  Y. 

Masses  of  iron  occur  at  the  Parrish  iron  mine,  St.  Lawrence 
Co.,  in  a  position  which  shows  that  the  ore  was  protruded  subse- 
quent to  the  deposition  of  the  Potsdam  sandstone.  The  rock  in 
this  case  being  disturbed  at  the  time  of  its  eruption. 


Fig.  42. 


Atlantic  Curren 


CHAPTER  VIII. 

SECOND  SYSTEM,  THE  LAMINATED  PYRO-CRYSTALLINE  ROCKS, 
GNEISS  AND  ALLIED  COMPOUNDS. — THIRD  SYSTEM,  THE  PYRO- 
PLASTIC  ROCKS,  BASALT,  GREENSTONE,  TRAPS,  PORPHYRIES,  ETC. 

87.  THIS  system  embraces  gneiss,  mica  slate,  hornblende  rock, 
and  talcose  slate ;  sometimes  they  pass  into  quartz.     To  the  fore- 
going it  is  necessary  to  add  limestone  and  serpentine,  inasmuch  as 
both  have  a  laminated  structure  under  certain  circumstances. 

88.  Gneiss. — Gneiss  has  the  same  component  elements  as  gra- 
nite, but  they  are  arranged  in  parallel  lines  or  bands ;  and  hence 
it  has  a  very  close  resemblance  to  a  stratified  rock.     Indeed,  it  is 
placed  by  many  in  this  class.      But  we  believe  its  structure  is  due 
to  the  circumstances  under  which  it  cooled.     Thus,  its  laminae  are 
always  made   up  of  different  crystallized   minerals,  which,  while 
undergoing  this  process,  separate  from  the  mass  to  that  extent  that 
the  layers  become  individualized.    There  is  probably  also  a  state  of 
tension  occasioned  by  the  pressure  of  the  mass  beneath. 

89.  That  there  is  a  force  competent  to  arrange  the  elements  in 
distinct  bands,  when  they  are  intimately  mixed,  is  proved  by  many 
examples :  the  flint  of  chalk  beds,  the  septaria  in  slate,  and  the 
silicious  nodules  of  the  carboniferous  limestone,  are  examples  in 
point.    In  these  instances  we  are  obliged  to  recognise  a  force  which 
separates  one  mineral  from  another,  as  silex  from  clay,  or  silex  from 
limestone,  or  carbonate  of  limestone  from  clay.     In  all  these  in- 
stances layers  or  nodules  may  be  formed.    The  laminae  of  gneiss  do 
not  differ  so  widely  from  those  produced  by  the  molecular  force,  to 
which  we  have  referred,  as  to  prove  that  their  occurrence  need  be 
assigned  to  a  different  cause,  as  that  of  deposition. 

The  same  force  has  operated  also  in  mica  and  talcose  slates  and 
hornblende  rock. 

Gneiss  is  a  granitoid  rock,  and  frequently  passes  into  granite ;  and 
it  is  probable  that  the  former  may  be  regarded  as  the  superior  part 
of  a  mass  of  granite.  In  other  instances  it  is  inseparable  from 
mica  slate,  and  others  which  belong  to  this  class. 

(64) 


LAMINATED   PYRO-CRYSTALLINE   ROCKS.  o5 

This  rock  is  also  porphyritic :  crystals  of  felspar  stand  out  upon 
its  surface  in  consequence  of  weathering,  while  the  laminae  are  quite 
distinct.  It  often  resembles  granite,  and  large  areas  of  such  a  mass 
may  be  a  true  granite;  the  size  and  numbers  of  the  individual 
crystals  obliterating  the  laminated  structure. 

Fig.  43  represents  the  parallel  arrangement  of  the  minerals  com- 
posing a  mass  of  gneiss.  The 
laminae,  however,  are  not  al- 
ways straight.  They  often  ex- 
ist in  curves  or  folds,  or  even 
in  zigzag  lines.  A  mecha- 
nical force  seems  in  many  in- 
stances to  have  produced  these 
varieties. 

90.  Mica     Slate. Typical  '      Structure  of  Gneiss. 

Mica  Slate  is  composed  of  quartz  and  mica.  The  color  is  gray, 
varying  from  light  to  dark.  It  has  a  shining  appearance  and  strong 
lustre.  The  mica  is  usually  in  small  particles ;  talc  is  often  inter- 
mixed with  it,  and  small  crystals  of  hornblende  are  also  often  found. 

91.  Hornblende  Hock. — In  this  rock  Hornblende  exists  in  large 
proportions,  intermixed  with  grains  of  feldspar,  quartz,  mica,  and 
talc ;  but  hornblende  and  feldspar  predominate  and  generally  com- 
pose the    entire  mass.     The   color   is   usually  dark  green.     The 
arrangement  of  the  minerals  is  similar  to  that  in  gneiss ;  the  feld- 
spar and  hornblende  being  arranged  in  separate  planes. 

92.  Talcose  Slate. — This  rock  is  composed  of  quartz  and  talc. 
The  quartz  predominates ;  but  the  talc  being  more  conspicuous,  im- 
parts its  own  character  to  the  rock.     It  is  of  a  light  greenish  gray 
color  with  a  silvery  lustre.     The  laminae  are  frequently  corrugated ; 
the  corrugated  condition  is  far  more  constant  in  this  rock  than  in 
mica  slate,  or  gneiss.     Beds  of   closely  compacted  talc   form  the 
well  known  soapstones.     Beds  in  which  talc  is  almost  entirely  ex- 
cluded, form  a  variety  of  quartz  rock,  which  may  be  mistaken  for  a 
sandstone  of  sedimentary  origin,  as  at  Pilot  Knob  in  North  Caro- 
lina.    Milky  quartz  is  a  common  mineral  in  the  talcose  slates.     It 
occurs  in  irregular  seams.     Fig.  44,  a,  b,  c,  shows  the  structure  of 
granite,  gneiss,  and  talcose  slate. 

93.  Distribution  of  Gneiss,  Hornblende,  Mica  Slate,  and  Talcose 
Slate. — These  rocks,  with  a  few  exceptions,  form  the  White  Hills 

G* 


66 


MANUAL    OF    GEOLOGY. 
Fig.  44. 


a  Granito. 


c  Talcose  Slate. 


of  New  Hampshire,  the  Green  Mountains  of  Vermont,  the  Hoosic 
Range  of  Massachusetts,  the  Blue  Ridge  of  the  Southern  States. 

94.  The   Laminated  Limestones   and  Serpentine. — There    are 
numerous  instances  where  Limestone  and  Serpentine  are  interlami- 
iiated  with  the  foregoing  rocks.    In  most  cases  they  partake  of  their 
structure.     This  structural  phenomenon  is  not  well  understood,  and 
it  is  necessary  only  to  refer  to  the  fact  and  state  one  or  two  locali- 
ties.    The  limestones  of  Middlefield,  Mass.,  where  it  is  crossed  by 
the  Western  Railway,  is  a  good  example  of  this  variety  of  lime- 
stone :  and  an  extensive  bed  of  serpentine  in  Macon  Co.,  N.  C.,  is 
a  remarkable    one   for    serpentine.     In   this   connection  we   may 
observe  that  trap  and  porphyry  sometimes  appear  like  the  laminated 
rocks,  as  at  Essex  on  Lake  Champlain. 

95.  Jttetak j  Ores,  and  Sulphurets  of  this  System. — Gold,  in  the 
Southern  States,  the  eastern  slope  of  the  Green  Mountains,  and  in 
Canada,  is  a  common  product.     It  is  sometimes  contained  in  pure 
quartz,  white  as  loaf  sugar,  and  also  associated  with  the  sulphurets 
of  iron  and  copper,  and  is  no  doubt  in  chemical  combination  with 
sulphur,  as  it  is  impossible  by  mechanical  means  to  separate  the 
gold  from  the  sulphurets  or  sulphides. 

96.  A  Summary  of  the  Leading  Facts  respecting  the  Pyro-crys- 
talline  Rocks,  or  those  composing  th<    First  and  Second  Systems. — 

Division. 

PYRO-CRYSTALLINE. 
Structure. 

1st.  Massive  Pyro-crystalUne.  2d.  Laminated  Pyro-crystalUne. 

Names. 


Granite  and  Syenite. 
Pyro-crystalline  Limestone. 


Gneiss. 
Hornblende  Slate. 


LAMINATED   PYRO-CRYSTALLINE   ROCKS. 


67 


Serpentine. 
Rensselaerite. 
Octahedral  Iron. 
Hypersthene  Rock. 

Remarks. 

May  be  intrusive,  but  are  often 
overlying. 


Mica  Slate. 
Talcose  Slate. 
Laminated  Limestone. 
Serpentine. 

Usually  overlying,  but  do 
not  occur  in  a  certain  order, 
and  never  intrusive. 


Fig.  45. 


Afirondack  Pass.    Cliff  of  Hypersthene  rock,  1000  feet  perpendicular. 


CHAPTER  IX. 


THE   PYRO-PLASTIC   ROCKS. 

97.  THIS  series  of  rocks  are  distinguishable  from  the  pyro-crys- 
talline  by  the  state  of  aggregation  in  which  they  exist.     They  are 
more  homogeneous  and  compact  than  common  granite,  and  crystals 
of  feldspar  are  common  as  in  the  porphyries.     Fig.  46  represents 

an  instance  where  anjni- 

Fig.  46. 

lar  masses  are  imbedded 
in  a  compact  paste. 

These  rocks  should  be 
divided  into  two  groups : 
1st.  the  Submarine,  2d. 
the  Subaerial.  These 
names  indicate  the  cir- 
cumstances under  which 
they  were  cooled.  Those 

ijritio  structure.  belonging   to    the    -Sub- 

marine division,  the  basalts,  greenstone,  amygdaloid,  trap,  por- 
phyry, and  clinkstone,  it  is  supposed  were  erupted  under  the  waters 
of  an  ocean,  or  cooled  under  a  great  pressure. 

Basalt  is  black,  fine  grained,  and  compact;  it  is  both  massive 
and  columnar. 

98.  Greenstone  and   Trap. — Greenstone  differs   from  basalt  in 
being  somewhat  crystalline,  and  usually  contains  crystallized  par- 
ticles, but  to  the  unassisted  eye  it  is  in  the  main  homogeneous. 
When  these  form  masses  which  are  confined  or  bounded  by  parallel 
walls,  composed  of  other  kinds  of  mineral  matter,  they  are  called 
trap  dykes.     Dykes  are  sometimes  slightly  columnar.     (Fig.  47). 

Trap  and  greenstone  are  often  vesicular,  and  the  vesicles  are 
filled  with  foreign  matter;  this  is  called  amygdaloid. 

99.  If  masses  ring  when   struck  with  a  hammer,  it  is  called 
clinkstone. 

(68) 


IGNEOUS    ROCKS. 


69 


Fig.  47. 


Fig.  48. 


;  I 

Fig.  47  represents  a  trap  dyke,  a,  a,  granitic  veins :  6,  trap  dyke.  It  will  be 
seen  the  trap  cuts  the  granite  veins;  showing  that  the  trap  was  injected  subse- 
quent to  the  granite.  The  figure  shows  that  a  dislocation  or  shift  has  taken  place. 

Fig.  48  represents  trap  dykes  intersecting  other  rocks  :  a,  b,  mass  of  pyro-crys- 
talline  limestone,  d,  d,  d,  trap  dykes;  c,  a  vein  of  octahedral  iron. 

Trap  dykes  and  greenstone  are  of  all  ages.  The  former  are 
formed  in  nearly  straight  fissures,  and  often  may  be  traced  in  nearly 
a  direct  line  for  many  miles,  and  with  very  little  variation  in  width. 

100.  Origin  of  this  Series. — All  the  varieties  which  we  have 
described  are  igneous  products,  and  have  issued  from  the  interior 
of  the  earth  through  rents.     The  molten  matter  has  overflowed  the 
surrounding  surface,  or  has  been  forced  between  the  strata  of  other 
rocks.     The  upper  surface  has  in  some  instances  been  compara- 
tively free  from  pressure,  and  the  confined  vapors  expanding  have 
formed  cavities,  as  in  the  amygdaloids.     These  cavities  were  after- 
wards filled  by  transfusion  through  the  mass  of  rock  by  means  of 
water  carrying  in  solution  the  elements  of  various  bodies,  as  anal- 
cime,  stilbite,  calcspar,  prehnite,  &c. 

101.  Subaerial  Division. — The  rocks  belonging  to  this  division 
include  lavas  and  all  matters  which  have  issued  from  the  craters 
of  volcanoes.      Flowing  in  a  liquid   form,  large   areas   are  often 
covered  with  the  molten  rock.     When  cooled  and  solid,  it  is  black, 
porous,  and  vesicular  or  homogeneous,  vitreous  or  similar  to  the 
slags  from  a  furnace,  and  beneath,  in  consequence  of  the  pressure 
of  the  superincumbent  mass,  it  is  nearly  compact ;  its  vesicularity 
increases  from  the  bottom  to  the  top,  (fig.  50) ;   c,  columnar  green- 
stone ;  I,  porphyrittc ;  a,  lava.     Ashes  and  stones  also  issue  from 
volcanoes  which  fall  in  part  around  the  orifice  and  form  a  cone, 
or  are  carried  by  winds  to  neighboring  parts,  or  even  to  distant 
countries.     Pumice  is  a  light  gray  fibrous  glass ;  so  light  as  to  float 


70 


MANUAL   OF   GEOLOGY. 


upon  water.    Obsidian  is  a  volcanic  glass  and  free  from  vesicles,  and 
breaks  with  a  conchoidal  fracture. 


Fig.  49. 


Fig.  49  shows  the 
columnar  variety  of 
green. stone;  c  is  a 
mass  forced  in  be- 
tween beds  of  new 
red  sandstone;  b, 
the  columnar  part. 


102.  Tabular  View  of  the  Members  of  this  System. 

Origin. 

Igneous. 

Division. 

PYRO-PLASTIC. 


1.  Submarine, 


2.  Subaerial.    - 


Names. 
Basalt. 

Greenstone  and  Trap. 
Porphyry. 
Clinkstone. 


Lava. 

Ashes. 

Pumice. 

Obsidian. 


Remarks. 

Erupted  through  fissures  and 
cooled  under  pressure.  Structure 
<  compact;  sometimes  there  are  crys- 
I  tals  in  a  compact  base.  When  vesi- 
I  cular,  the  cavities  are  lined  with 
J  crystals. 

Erupted  through  craters  and 
cooled  in  the  air,  and  more  or  less 
resicular. 


CHAPTER  X. 

OP  THE  SEDIMENTS  OR  HYDRO-PLASTIC  ROOKS — AGENTS'  CON- 
CERNED IN  THEIR  PRODUCTION — RECOGNISABLE  BASE — 
PROGRESS  OF  LIFE  DURING  THE  SEDIMENTARY  PERIODS — 
AMOUNT  OF  SEDIMENTS — GEOLOGIC  TIME. 

103.  IT  was  an  important  era  when  vapors  began  to  condense 
upon  the  earth's  surface.     It  ushered  in  a  period  distinguished  by 
a  new  class  of  phenomena.     The  earth  felt  the  animating  effects 
of  this  new  agent;  and  these  effects  must  be  regarded  as  indicative 
of  progress. 

104.  The  sediments  are  due  to  mechanical  causes,  and  mainly 
to  attrition.     Atmospheric  agencies  are  preparative,  as  by  them  the 
surfaces  of  rocks  are  altered,  and  the  adhesion  and  force  of  aggre- 
gation among  particles  is  diminished  and  even  destroyed  ;  and  hence 
falling  water,  as  rain,  running  water,  as  in  brooks,  water  moving  in 
mass,  as  that  of  tides  and  waves,  are  much  more  effective  than  if 
left  simply  to  its  own  mechanical  powers.     Atmospheric  agencies 
are  much  more  active  on  mountains  than  elsewhere.     The  moist 
surface  and  the  effect  of  frost  break  down  rapidly  many  kinds  of 
rock,  especially  those  which  contain  alkalies  and  alkaline  earths. 
If  they  are  jointed,  they  are  slowly  reduced  in  size,  and  the  angular 
blocks  are  separated;  but  if  they  consist  of  silex,  they  may  resist 
disintegration  for  centuries.     Granites  are  more  subject  to  change 
in  consequence  of  their  composition;  and  schistose  rocks,  such  as 
mica  and  taleose  slates,  from  their  structure  and  component  parts. 
But,  whether  rapid  or  slow,  the  broken  rocks  tend  to  the  valleys ; 
and  the  streams.,  which  often  rush  forward  with  a  mighty  force  from 
the  hills,  are  constantly  employed  in  carrying  debris  from  their  tops 
and  sides  to  the  rivers  below.     The  special  destinations  are  to  the 
plains,  where  the  debris  may  be  left ;  or  lakes,  through  which  they 
flow ;  and,  finally,  the  ocean,  where  all  the  waters  ultimately  bring 
their  burthens.     The  fine  particles  are  committed  to  the  waves, 
tides,  and  ocean  rivers,  or  the  deep  and  superficial  currents,  and 
thereby  reach  those  destinations  which  gravity  and  the  direction  of 
the  moving  waters  may  determine. 

The  waters  of  the  ocean  are  distributive,  while  streams  and  rivers 

(71) 


72 


MANUAL   OF   GEOLOGY. 


are  transportive.  To  the  combined  effects,  then,  of  streams,  rivers, 
and  ocean  currents,  is  due  the  accumulation  of  the  sediments. 
While  their  activity  has  been  unceasing  and  continuous,  the  period 
during  which  they  have  thus  moved  is  susceptible  of  divisions  into 
stages,  each  of  which  is  distinguishable  from  the  rest.  The  sedi- 
ments are  monuments  constructed  by  the  agents  already  described : 
or  they  may  be  viewed  in  the  light  of  tablets  upon  which  are 
recorded  the  entire  history  of  the  sedimentary  period. 

The  peculiar  phenomena  which  belong  to  sediments,  as  a  whole, 
are  the  presence  of  pebbles,  fossils,  and  ripple  marks,  especially 
the  two  former :  the  latter  is  the  most  common  in  sandstones :  fig. 
51  illustrates  this  character. 

Fig.  51. 


Ripple  Marks. 


Of  the  sediments  we  maintain  that  we  have  a  recognisable  base,  the 
visible  beginning  of  a  vast  period ;  and  if  so,  it  follows  that  we  have 
also  a  palaeozoic  base,  to  which  we  may  point  as  the  beginning  of 
the  organic  kingdoms  when  the  creative  acts  of  God  spake  life  into 
dust,  from  which  successive  acts  both  of  creation  and  generation  have 
made  the  earth  a  scene  of  activity,  harmony,  beauty  and  progress. 
It  is  harmonious,  for  life  in  all  its  forms  and  phases  has  been 
adapted  to  every  special  physical  condition.  It  has  been  progres- 
sive, for  creation  began  with  the  lowly  organized  tribes,  and  pro- 
ceeded to  the  higher,  by  successive  upward  steps,  ending  with  man, 
whose  superior  rank  is  strikingly  told  by  his  erect  body,  ponderous 
brain,  and  upward  directed  vision. 

The  life  eras  both  of  plants  and  animals  began  at  the  extreme 
end  of  the  scale.  As  eras,  their  beginning  is  marine,  and  the  pecu- 


SEDIMENTS   OR   HYDRO-PLASTIC   ROCKS.  73 

liar  and  distinguishing  forms  of  life  were  obscure  and  lowly  organ- 
ized fuci,  or  the  coral  and  crinoid,  whose  functions  partake  largely 
of  the  vegetable  kind,  or  those  only  which  belong  to  the  lowest 
rank. 

105.  Instinctive  movements,  and  those  of  the  nutritive  functions 
alone,   distinguished  them  from  analogous  vegetable  forms;  and 
though  all  were  perfect,   and  well  adapted  to  fulfil  the  ends  of 
their  existence,  still  the  survey  of  long  periods  is  required,  before 
we  discover  the  higher  organizations  indicated  by  the  soft  and  solid 
parts, — brain  and  bone, — with   their  appendages;    combinations, 
necessary  it  would  seem,  for  a  more  vigorous  exercise  of  physical 
force  as  well  as  the  higher  adornments  of  life.     Often,  however, 
progress  is  at  a  standstill,  or  creeps  lazily  forward  in  doubtful  garbs 
or  habiliments ;  some  of  which  are  frequently  suspected  to  have 
been  indicative  of  degradation;  but  a  deeper  insight  into  struc- 
ture, form,  and    combination  proves,   that  nature   is   moving  on 
slowly,  but  with  progressive  steps,  to  that  goal  of  perfection  which 
this  system  of  arrangements  is  destined  to  attain. 

When  trees  and  forests  adorn  the  earth,  the  sediments  have 
already  attained  half  their  thickness,  and  it  is  only  in  the  middle 
periods  that  reptilian  life,  a  second  stage  in  advance  of  the  verte- 
brates, is  represented  in  the  ancient  earth's  fauna.  Not  even 
birds,  or  any  vertebrates  with  warm  blood,  are  yet  living,  and  when 
they  appear  in  the  Mesozoic  division,  they  belong  to  the  lowest  of 
their  respective  classes ;  and  it  is  only  in  the  Cainozoic  division, 
that  the  rocks  disclose  to  us  the  highest  grades  of  structure,  com- 
bined with  a  development  of  brain  and  bone  indicative  of  intelli- 
gence, social  habits,  and  a  love  of  kind. 

Thus,  though  at  first  the  life  forms  are  beautiful  without  and 
within,  as  structures,  yet  they  exhibit  no  results  belonging  to  brain- 
influence.  They  are  only  vegetative  beings  guided  by  instinct. 
Thus,  comparing  the  extreme  with  the  middle,  and  the  middle  term 
with  the  present  or  the  Cainozoic,  the  proposition,  that  life  has  been 
progressive  and  developed  in  stages,  is  as  well  established  as  any 
connected  series  of  events  in  the  history  of  the  by-gone  nations 
of  the  East. 

106.  The  characters  of  the  sediments  vary  with  the  source  from 
whence  they  were  derived,  and  the  force  of  the  transporting  agent. 
With  every  change  of  level,  new  kinds  of  sediment  are  borne  for- 
ward, and,  accompanying  this  change,  the  sediments  are  necessarily 
coarser.     If  a  change  of  level  is  considerable,  the  direction  of  all 


74 


MANUAL   OF   GEOLOGY. 


tlie  surface  streams  is  changed  also;  and  as  their  motions  must 
be  tumultuous,  stones  and  rocks  are  transported,  and,  hence,  the 
conglomerates  are  formed  which  usually  mark  the  beginning  of  a 
new  era.  These  changes  of  level  of  the  earth's  crust  seem  to  have 
been  incompatible  with  the  existence  of  the  species  then  living 
upon  the  area  affected ;  and,  hence,  extinction  follows  the  change. 

When  the  waters  move  quietly  again,  we  find  that  new  species 
are  created  fitted  to  take  the  places  of  those  which  have  perished. 
It  is  a  part  of  the  duty  of  the  geologist  to  note  particularly  those 
physical  changes  by  which  new  kinds  of  matter  accumulate,  and 
new  living  species  are  taking  the  place  of  those  which  have  passed 
away.* 

A  succession  of  beds,  or  of  rock,  is  no  doubt  to  be  attributed 
mainly  to  the  changes  of  level,  in  the  earth's  crust.  And  so,  also, 
we  may  assume,  the  succession  of  fossil  remains  is  due,  in  part,  to 
the  same  cause. 

107.  Sediments  are  usually  deposited  in  parallel  beds ;  but  not 
always.  When  they  are  deposited  from  tumultuous  waters,  or 
when  deposits  are  undermined,  and  their  position  is  changed,  it 
often  happens,  that  the  beds  exhibit  a  diverse  stratification,  as 
represented  in  Fig.  52. 

Fig.  52. 


Diverse  Stratification. 

Sediments,  we  have  said,  have  not  always  been  deposited  hori- 
zontally. Such  a  view  is  disproved  by  observations  upon  a  sea- 

*  It  is  evident  that  changes  of  level  have  affected  and  will  affect  those  mollusks 
which  inhabit  shallow  water,  while  those  which  inhabit  deep  seas  may  escape  the 
injurious  effects  incident  to  a  moderate  change  of  level.  But  those  inhabiting  the 
deep  parts  of  seas  would  not  probably  escape  entirely  from  the  disastrous  effects  of 
a  change  of  level,  since  the  waters  would  be  less  deep,  and  since,  too,  they  are  fitted 
to  those  greater  depths  rather  than  those  which  are  shallow.  So,  also,  great  sub- 
sidences of  the  ocean's  bottom,  have  been  equally  destructive  to  life.  We  may, 
therefore,  regard  the  position  as  established,  that  changes  of  level  have  been  the 
principal  cause  of  the  extermination  of  marine  animals  in  former  periods. 


SEDIMENTS    OR    HYDRO-PLASTIC    ROCKS.  75 

shore,  when  the  surface,  or  bottom,  is  inclined  sometimes  steeply ; 
and  yet  deposits  are  taking  place  upon  these  slopes.  Inclined  beds, 
therefore,  are  formed  during  their  deposition  upon  the  borders  of 
an  ocean,  without  having  been  subjected  to  an  upheaval.  Various 
changes,  too,  affecting  their  position,  are  going  on;  portions  are 
washed  away,  forming  thereby  depressions;  prominences  are  sliced 
off,  and  yet  the  process  of  deposition  goes  on.  Hence,  there  may 
appear  to  have  been  breaks,  and  certainly  many  curious  uncon- 
formities will  occur,  especially  in  sandy  deposits.  Sediments,  then, 
cannot  be  represented  by  a  pile  of  books  stacked  up  in  exact  order. 
So,  toOj  beds  may  be  elevated  over  a  large  area  and  cease  to  receive 
accessions  of  sediment.  These,  in  after  times,  may  be  depressed, 
and  again,  when  debris  accumulates,  they  are  placed  in  a  true  un- 
conformability.  Between  their  elevation  and  their  going  down,  or 
during  the  time  they  were  dry  land,  distant  sediments  have  accu- 
mulated in  which  animals  and  plants  are  preserved,  and  which 
thereby  become  the  historic  records  for  this  interval. 

It  follows,  then,  that  geologic  history  is  often  incomplete  in  the 
sediments  of  one  country.  Who  would  expect  to  find  a  complete 
history  of  the  American  Revolution  in  our  own  archives  ?  For  that 
we  go  to  England,  France,  and  Germany,  in  order  to  complete  the 
record  of  events  for  a  few  years.  The  sequence  of  geologic  records 
is  complete,  the  sequence  of  events,  too,  is  complete,  but  not  in 
any  one  country,  yet  ^sediments  are  frequently  deposited  in  hori- 
zontal layers;  they  belong  to  the  deep  sea,  far  from  land,  and  away 
from  the  influence  of  tides  and  currents. 

108.  Amount  of  Sediments. — It  is  impossible  to  calculate  accu- 
rately the  quantity,  or  mass  of  the  sediments.  The  area  occupied 
by  the  mountain-chains  upon  the  globe,  is  small  compared  with  the 
extent  of  the  plains  and  gently  rolling  surfaces.  Besides,  the  sea 
conceals  and  covers,  no  doubt,  a  much  greater  amount  than  is 
lifted  above  its  level.  It  is  true,  that  over  large  areas  the  sedi- 
ments are  thin,  especially  those  belonging  to  the  latest  periods. 
But  it  is  stated,  by  good  authority,  that  they  are  at  least  ten  miles 
thick, — a  statement  which  is,  no  doubt,  below  the  truth ;  but  if 
this  is  received  as  an  approximation  to  the  truth,  it  is  evident,  that 
the  sediments  are  sufficient  to  form  more  than  a  score  such 
mountain  systems  as  those  which  now  exist. 

Then  it  is  to  be  remembered,  that  it  has  all  been  mechanically 
worn  from  preexisting  rocks;  and  when  it  is  considered,  that  a 


76  MANUAL    OF    GEOLOGY. 

timjle  sandstone  rock,  composed  only  of  some  hundred  layers,  must 
have  occupied  a  long  time  in  its  deposition,  we  may  feel  satisfied, 
that  we  are  not  presuming  too  much,  when  we  assign  an  immense 
or  inconceivable  lapse  of  time  to  the  period  which  has  been  con- 
sumed in  the  deposition  of  all  the  sediments. 

The  facts  relative  to  the  amount  of  sediments  bear  directly  upon 
the  question  relative  to  the  age  of  the  world,  and  especially  to  the 
time  which  has  elapsed  since  the  earth  became  inhabitable.  The 
approximate  estimation,  then,  fully  warrants  the  conclusion  we  have 
stated. 

Vegetable  and  animal  life  also  confirms  the  proposition,  that  the 
time  since  this  creation  began  was  immense. 

109.  In  the  foregoing  sections  reference  has  been  made  to 
geologic  time.  Time,  when  referred  to,  implies,  in  common  usage, 
a  period  which  can  be  measured ;  and  the  first  idea  of  the  student 
in  geology  is,  that  geologic  time  is  measured,  like  secular  time,  by 
the  year  and  its  parts.  Attempts  have  been  often  made,  to  con- 
vert geologic  time  into  secular ;  that  is,  to  compute  the  epochs,  or 
periods,  by  years.  But  these  attempts  have  failed.  Time  in 
geology,  is  not  absolute,  but  relative.  Time  considered  in  human 
aifairs,  is  both  absolute  and  relative;  and  it  is  absolute,  because  it 
has  its  units.  A  rotation  of  the  earth  upon  its  axis  is  the  unit, 
and  its  revolution  around  the  sun  is  something  more  than  365  of 
these  units.  These  revolutions  and  rotations  express  constant  and 
ever  recurring  periods.  All  events,  which  have  transpired  since 
man  was  created,  have  a  fixed  relation  to  these  units.  As  re- 
gards man  and  events,  there  is  a  unit  and  a  known  starting  point. 
Now,  geologists  have  failed  in  attempting  to  compute  by  absolute 
time,  because  they  could  neither  obtain  a  unit  nor  a  starting  point. 
Sir  Charles  Lyell  has  counted  the  layers  in  the  sediments  of  the 
delta  of  the  Mississippi,  and  measured  the  suspended  mud  in  the 
waters  which  it  brings  to  its  delta  and  to  the  sea.  Rationally,  it 
carried  him  back  40,000  years  since  the  delta  began  to  form ;  but 
his  unit  was  a  layer  of  mud,  and  hence,  when  all  the  circum- 
stances are  considered,  is  entirely  problematical,  or  approximative 
only.  So,  also,  he  has  counted  the  steps  of  the  Niagara  as  it  has 
receded  from  a  lower  towards  an  upper  lake.  But  here  the  steps 
are  unequal,  and  hence  gave  him  no  unit  in  its  march.  Unlike  the 
earth  and  planets  moving  in  their  orbits  and  completing  their  re- 
volutions in  equal  times,  we  find  that  all  geological  movements  are 


SEDIMENTS   OR   HYDRO-PLASTIC   ROCKS.  77 

too  unequal  from  their  nature  and  so  much  exposed  to  perturbations, 
that  geologists  have  failed  to  obtain  an  exact  unit  by  which  they 
can  measure  periods  or  epochs.  Geologic  time  is,  therefore,  relative; 
and  all  epochs  and  periods  have  relations  in  time  to  others,  and  are 
never  computed  in  years  or  definite  cycles. 

110.  While  then  we  speak  of  geologic  time  as  relative,  because 
we  have  nc  unit  to  measure  it  by,  we  cannot  fail  to  discover  in  the 
sequel,  that  it  is  really  vast ;  or,  indeed,  scarcely  measurable  at  all. 
Indeed,  geologic  time  is  only  comparable  to  astronomical  space.    It 
is,  however,  not  like  space,  infinite,  but  it  is  vast.     We  obtain  an 
approximate  measurement  of  time  by  masses  of  sediment  which  have 
accumulated  during  the  epochs;  each  of  which  must  have  been 
vast  also.    The  mode  of  measurement  is  analogous  to  that  pursued 
by  astronomers.     It  is  a  division  of  masses  into  stages,  which  are 
separably,  and  also,  in  the  aggregate,  more  comprehensible,  than  if 
we   attempted  to   conceive  of  them  in  their  totality.     The  beds 
composing  the  Silurian,  Devonian,  and  Carboniferous  rocks,  which 
may  be  regarded  as  portions  of  space,  represent,  in  one  sense,  time, 
are  measurable ;  and  if  we  assume,  as  probably  we  may,  that  the 
past  was  like  the  present  in  its  modes  of  action,  it  follows,  if  we 
have  observed  and  measured  the  progress  of  the  present,  that  we 
may  obtain  approximate  ideas  of  the  past.    But,  then,  we  are  ever 
brought  back  to  the   vastness  of  geologic  time,   precisely  as  the 
astronomer,  who  gauges   the   depth   of  astronomic  space  without 
ever  being  able  to  measure  the  bounds  in  which  matter  is  dis- 
tributed. 

111.  There  is  no  fact  which  is  better  established,  than  that  of  a 
succession  of  organic  beings.     It  rests  on  evidence  equally  firm,  as 
the  succession  of  rocks.     Succession  and  replacement  are  the  two 
great  geological  facts.     As  we  have  already  intimated,  the  physical 
changes  are  also  successive;  but  there  is  something  more  in  geolo- 
gical succession  than  the  word  seems  to  imply; — the  succession  is 
one  that  advances  from  a  stage  of  disturbance  to  one  of  rest;  from 
imperfection  to  perfection;  and  each  change  is  itself  a  progress, 
and  it   is    also   preparative.      But  progress  is   often   confined  to 
specializations,    and    this    has  often  deceived    philosophers ;    for, 
though  it  is  usually  the  highest  evidence  of  progress,  it  has  some- 
times been  confounded  with  degradation.     Geologists,  recognising 
the  principle  of  succession,  have  sought,  with  avidity  and  success, 
the  chronology  of  organic  beings,  or  the  time  when  the  families, 

7* 


78 


MANUAL    OF    GEOLOGY. 


composing  the  organic  world,  first  appeared,  and  also,  in  connection, 
the  doctrine  of  replacement,  have  sought  to  determine  when  they 
disappeared,  and  who  and  what  replaced  them  in  the  succeeding 
group. 

But  there  is  a  more  general  view  than  the  preceding,  as  it  re- 
gards succession.  It  goes  further  back.  It  takes  in  the  considera- 
tion of  the  elementary  tissues.  Animals,  as  we  have  seen,  are 
composed  of  muscle,  nerve,  bone,  &c.  At  what  period  did  bone  and 
brain  appear,  for  they  go  together ;  for  though  the  nervous  system 
existed  from  the  beginning  in  some  low  stage,  yet,  bone  and  brain 
proper,  seem  to  be  linked  together  in  time.  Cellular  tissue  is  the 
connecting  structure  for  all  organs,  and  is  no  doubt  the  oldest  of 
all.  In  plants,  we  have  the  cdlulares,  which  represented  at  one 
period  the  whole  vegetable  kingdom.  But  there  are  particular 
modifications  of  cellular  structure  which  are  not  thus  universal. 
Thus  the  peculiar  structure  of  bone  is  confined  to  bone  ;  bone- 
cells  are  confined  to,  or  limited  to  bone;  and  animal  structures,  taken 
in  classes,  have  each  their  peculiar  modifications.  The  bone  of  the 
bird,  for  example,  may  be  distinguished  from  the  bone  of  a  quad- 
ruped ;  and  the  bone  of  the  fish,  also,  from  the  other  classes.  But 
the  most  interesting  fact  representing  bone  structure  and  bone-cells 
is,  the  permanence  of  the  pattern.  For  example,  the  bone-cells  of 
the  earliest  fish  cannot  be  distinguished  from  fish  of  our  rivers  and 
oceans.  The  bone-cells  or  the  cells  of  any  tissues,  have  not  changed 
in  time.  Hence  it  is,  that  uniformity  has  been  preserved,  as 
the  structures  are  built  into  forms  complete,  and  yet  the  plan  is 
not  altered.  The  external  form  may  be  changed,  yet  the  intimate 
structure  is  now  what  it  was  in  the  days  of  the  Old  Red  Sandstone, 
or  Carboniferous  system. 


Fig.  53. 


Fig.  54. 


A  Living  Conifer. 


To  show  this 
fact  we  have 
placed  side  by 
side  the  ancient 
conifer  (fig.  53), 
with  the  conifer 
of  our  present 
forest  (fig.  54). 

112.  So  also 
the  bone  of  an 
ancient  reptile  is 


SEDIMENTS    OR    HYDRO-PLASTIC    ROCKS. 


Bono  Cells  of  Ancien 


Fig.  56. 


identical  with  the  bone  of  the  F{9>  55. 

reptile  of  the  nineteenth  cen- 
tury :  fig.  55,  bone  cells  of  an 
ancient  fish :   fig.   56,  1,  bone 
cell  of  a  recent  fish:    2,  of  ai 
reptile  :    3,  of  a   bird ;  4  ,    of  |j 
a  mammal.     There   have  been 
myriads  of  organic  existences, 
yet  there  has  been  no  deviation  in 
the  patterns  of  structure.     In  all 
the  ancient  or  extinct  beings,  the 
pattern  has  been  followed  through- 
out in  the  modern  ;  and  hence  to 
find  original  types  we  have  to  go 
back;  and  our  language  should  in- 
dicate a  comparison  of  the   pre- 
sent with  the    past,  and  not  the 
past  with  the  present. 

To  preserve  these  uniformities, 
as  they  exist  in  the  primordial 
types,  required  one  wiU.  This  is 
the  essential  of  uniformity.  These 
structures  are  the  real  constants 
of  organization,  as  much  as  the 
determinate  forms  of  crystals  are 
the  constants  of  the  inorganic  kingdom. 

112.  We  should  not  conclude  our  general  remarks  upon  the  sedi- 
ments, without  offering  our  views  upon  Metamorpkism.  Thus, 
rocks  which  are  truly  metamorphic  are  either  connected  with 
those  of  igneous , origin,  or  erupted  ones;  or  else,  their  relations  are 
such  that  geologists  are  furnished  with  a  clue  to  the  cause  or  causes 
which  were  operative  in  effecting  the  changes  which  they  have  suf- 
fered. It  is  at  the  same  time  true,  that  changes,  to  a  limited  extent, 
have  taken  place  without  the  instrumentality  of  a  visible  agent.  It 
is  often  necessary  in  these  cases,  to  refer  them  to  a  general  prin- 
ciple or  law,  which  has  been  frequently  referred  to  in  this  work 
as  a  molecular  force.  It  is  under  the  influence  of  this  force,  that 
particles  composing  the  sediments  are  rearranged;  limestones, 
for  example,  pass  into  a  crystalline  condition,  and  the  slates  are  cut 
up  into  tabular  plates  of  a  rhombic  form,  &c., — a  fact;  which  may 


Bone  Cells  of  Fish,  Reptile,  Bird,  and  Mammal. 


80 


MANUAL   OF    GEOLOGY. 


often  be  accounted  for  on  the  ground  of  great  pressure  and  the 
influence  of  a  molecular  or  crystalline  force.  Metamorphism  is  no 
doubt  due  to  two  principal  causes :  heat  derived  from  the  interior 
of  the  earth  or  the  presence  of  eruptive  rocks,  and  molecular 
force  aided  by  the  presence  of  water. 

Water  is  probably  always  present  in  sediments,  and  to  its  presence 
is  due  in  part,  the  mobility  of  their  particles;  indeed  we  have 
reason  to  believe  that  a  mass  may  exist  in  a  semi-plastic  state,  in 
consequence  of  which  a  re-arrangement  of  the  particles  will  take 
place.  Crystallization  will  then  occur.  Hence,  many  of  the  lime- 
stones are  coarsely  crystalline.  Another  class  of  rocks  have  been 
called  metamorphic,  which  are  scarcely  entitled  to  the  appellation. 
We  refer  to  those  into  which  talc  and  mica  enter  largely  as  consti- 
tuents. In  rocks  thus  constituted,  we  have  no  occasion  to  infer  that 
the  mica  or  talc  has  crystallized  from  the  mass ;  it  is  rather  to  be 
inferred  that  they  are  simply  derivative,  and  exist  in  the  condition 
they  originally  were  in  the  parent  rock,  excepting  that  their  size 
has  been  diminished  by  attrition. 

Fig.  57. 


Paradoxides  ?  quadrispinosus  of  the  Tacouic  slate*, 


CHAPTER  XL 

TACONIO   SYSTEM — DIVIDED    INTO    UPPER   AND    LOWER — FOSSILS 
OF   BOTH   DIVISIONS. 

113.  THIS  system*  deserves  the  special  attention  of  geologists 
for  two  reasons  :  1st.  It  is  probably  the  base  of  the  Sediments ; 
2d.  It  is  also  probable,  that  it  is  the  Palaeozoic  base,  and,  in  both 
respects,  it  must  be  regarded  as  the  oldest  series  of  the  sedimentary 
class.  As  mechanical  sediments,  they  should,  as  a  whole,  bear 
more  than  any  subsequently  formed  rocks,  the  aspect  of  the  primary 
or  pyro-crystalline  ones;  especially  those  beds  which  were  first  de- 
posited. Such  is  the  case  :  it  is  difficult  to  distinguish  them  from 
the  rocks  from  which  they  were  derived.  This  is  particularly  so 
with  those  members  in  which  talc  and  mica  are  intermingled. 

As  the  Palaeozoic  base,  it  is  interesting  from  the  indications 
the  sediments  furnish  of  the  condition  of  the  earth  at  the  time 
when  plants  and  animals  were  first  created,  and  also  the  peculiar 
forms  which  peoplejl  it  in  the  dawn  of  their  existence.  At  this 
period  we  have  reason  to  assume,  that  the  temperature  of  the  earth 
was  higher  than  it  is  now;  but  not  to  that  degree  as  to  be  incom- 
patible with  the  life  of  animals  as  they  are  now  constituted.  It  is 
evident  from  the  disturbances  to  which  these  rocks  have  been 
subjected,  that  the  earth's  surface  was  subject  to  great  oscillations, 
and  that  chemical  forces  acted  with  considerable  energy,  probably 
greater  than  at  any  subsequent  period. 

This  system  has  been  called  metamorphic,  probably  with  more 
propriety  than  any  other ;  yet  there  is  scarcely  in  any  case  so 
much  alteration  or  change  in  the  masses  composing  it  as  to  disguise 


*  It  is  proper  to  state  that  several  distinguished  Geologists  have  regarded  this 
system  as  the  Lower  Silurian;  or  as  the  equivalent  of  the  Champlain  group. 
According  to  their  views  the  quartz  rock  of  Berkshire  is  the  Potsdam  sandstone 
more  or  less  altered  by  heat;  the  Stockbridge  limestone  is  the  Trenton  lime- 
stone; and  the  slates  crowning  Graylock,  the  highest  land  in  Massachusetts,  are 
the  Utica  and  Hudson  River  slates  in  an  altered  condition.  This  locality  is 
the  spot  selected  with  a  special  reference  to  prove  the  foregoing  doctrine. 

(81) 


82  MANUAL   OF   GEOLOGY. 

their  sedimentary  origin.  The  lower  limestones  have  lost,  to  the 
greatest  extent,  the  peculiar  phase  which  belongs  to  this  class  of 
rocks:  The  silicious  rocks  are  often  vitrified,  or  have  lost  their 
granular  structure  in  a  measure. 

Regarding  this  period  as  one  during  which  the  mechanical  and 
chemical  forces  were  very  energetic,  we  are,  no  doubt,  furnished  with 
a  key  to  the  solution  of  all  the  phenomena  of  this  kind.  At  this 
period  thermal  springs  were,  no  doubt,  far  more  numerous  than  at 
present,  and  many  of  them  held  in  solution  large  quantities  of 
silex,  which,  when  deposited,  passed  into  the  condition  of  vitrified 
masses,  identical  with  the  beds  of  chert  and  hqrnstone  which  is  one 
of  the  common  rocks  of  the  system.  It  is  by  no  means  necessary 
to  conceive  a  high  degree  of  temperature  common  to  the  whole  sur- 
face of  the  globe,  but  that  the  surface  had  so  far  cooled,  that  the 
water  had  accumulated  in  oceans  and  seas,  and  that  waters  of  high 
temperature  were  merely  local  phenomena  as  now,  being  however 
more  numerous  and  upon  a  larger  scale. 

The  fossil  vegetables,  which  belong  to  this  series,  are  exclusively 
marine ;  in  the  upper  part  they  are  numerous. 

114.  The  animals  belong  to  three  great  divisions  of  the  animal 
kingdom  :  Articulata,  Mollusca,  and  Radiata.  They  represent  the 
lowest  forms  of  their  respective  types.  Thus  the  articulata  are 
represented  by  Crustacea  belonging  mostly  to  the  genus  Paradoxides; 
the  mollusca  are  either  Brachiopodes,  or  those  which  are  related  to 
them,  and  very  small;  and  the  radiata  are  the  lowest  forms  of 
Polypes,  and  are  similar  to  the  recent  fungites. 

The  fossils  of  this  system  are,  therefore,  of  the  lowest  rank; 
they  are  also  rare.  It  has  been  maintained,  that  the  rarity  of 
fossils  was  due  to  the  condition  of  the  rocks ;  that,  although  they 
may  have  been  as  numerous  as  in  the  Lower  Silurian  series,  yet, 
the  rocks  having  been  altered  by  heat,  the  organic  remains  were 
obliterated.  But,  unfortunately  for  this  view,  it  is  found  that  the 
parts  of  the  series,  which  cannot  be  regarded  as  changed,  are 
equally  as  barren  as  those  which  are  located  near  the  primary, 
and  which  are  in  the  immediate  region  of  metarnorphic  action.  It 
is,  therefore,  probable  that  the  paucity  of  organic  remains,  in  this 
system,  is  due  to  the  fact  that  it  was  not  a  period  abounding  in 
living  beings. 

While  those  which  are  found  are  interesting,  because  in  the 
present  state  of  our  knowledge  they  are  the  first  which  appeared 


TACONIC   SYSTEM.  83 

upon  the  globe,  they  belong  to  types  which  are  well  known  in 
our  present  seas,  notwithstanding  they  are  so  far  removed  in  time 
from  the  present.  This  confirms  what  we  have  maintained,  that, 
in  the  almost  innumerable  forms  of  organic  remains  which  belong 
to  the  different  periods  of  the  earth's  history,  none  are  known 
which  do  not  belong  to  one  of  the  four  Cuvierian  types,  which  are 
so  fully  represented  in  the  living  fauna  of  recent  times.  The  unity 
of  the  plan  of  creation  is  most  fully  confirmed  by  facts  which  are 
drawn  from  this  most  ancient  sedimentary  epoch. 

115.  The  distinguishing  features  of  the  rocks  of  this  period 
must  be  obtained  from  the  lithological  characters  of  the   rocks 
themselves,  and  from  their  relative  position.     They  are  conglome- 
rates— brecciated  conglomerates :  sandstones,  limestones,  and  slates, 
among  which  it  is  common  to  find  cherty  masses  of  considerable 
thickness  intercalated.     The  important  minerals  which  belong  to 
this  period  are  gold,  silver,  specular  oxide  of  iron,  haematites,  and 
manganese ;  galena  is  sometimes  found. 

116.  This  system  is  subdivided  into  Lower  and  Upper',  the  first 
consists  of  a  conglomerate  at  the  base,  succeeded  by  silicious  tal- 
cose  beds  of  considerable  thickness,  in  which  there  are  frequently 
pebbles ;  next  above,  are  three  thick  beds  of  sandstone,  separated 
by  talcose  slates ;  these  are  succeeded  by  the  Stockbridge  limestone. 
This  is  the  marble  of  Berkshire  county,  Mass.,  and  which  extends 
from  the  state  of  Vermont  to  Georgia.    The  Stockbridge  limestone 
is  succeeded  by  a  mass  of  slate  of  great  thickness,  the  upper  part 
of  which  is  suitable  for  roofing.  The  greatest  thickness  of  the  Lower 
Taconic  rocks  is  about  5000  feet.    The  upper  quartz  beds  are  often 
vitrified,  while  a  lower  one,  still  many  hundred  feet  nearer  the 
pyro-crystalline  rocks,  is  a  sandstone. 

Fig.  58  illustrates  the  Berkshire  masses.  This  section  begins 
with  the  lowest  beds  resting  on  gneiss  and  granite,  and  extends 
across  the  summit  of  Oakhill  in  Williamstown,  Mass.,  and  west 
through  the  valley  to  the  Petersburgh  range. 

1.  Conglomerate  at  base.  2.  Limestone.  3.  Slate.  4.  Conglomerates.  5. 
Slates.  6.  Sparry  Limestone.  7.  Slates.  C.  Overlying  Calciferous  Sandstone. 
////.  Fractures. 

The  section  fig.  59  is  designed  to  illustrate  the  equivalent  beds 
in  Buncombe  Co.,  N.  C.,  near  the  Warm  Springs.  The  conglo- 
merates upon  this  section  are  much  thicker  than  in  Berkshire  Co., 
and  the  lower  Taconic  is  much  more  perfectly  developed,  and  the 
quartz  is  much  more  vitrified.  The  materials  composing  the  con- 


84  MANUAL   OF   GEOLOGY. 

glomerates  in  each  section  are  derived  from  the   pyre-crystalline 
rocks  upon  which  they  rest. 

117.  The  Warm  Spring  Section,   N.    C.;   fig.  59,  exhibits  the 
following  series : — 

a.  Gneiss,  b.  Sienitic  Granite.  1.  Talcose  Slates  with  pebbles.  2.  Seamy 
Brown  Sandstone,  more  or  less  ferruginous.  3,  4,  and  5.  Slate  with  Pebbles.  6. 
Talcose  Jointed  Slates.  7,  7,  7.  Talcose  Slates.  8,  8.  Granular  quartz.  9.  Gray 
Limestone. 

Section  fig.  60  is  designed  to  show  the  position  of  the  granular  lime- 
stone of  Berkshire  Co.,  near  Graylock,  Williamstown,  Mass.  This 
rock  crops  out  upon  both  sides  of  Saddle  Mountain.  1.  On  the 
western  slope  facing  the  valley  of  Green  river.  2.  On  the  Adams 
side  of  the  same  range,  and  hence  forms  a  low  synclinal  axis.  Above 
the  limestone,  which  is  about  300  feet  thick,  is  a  thick  mass  of 
talcose  slate ;  below  it,  is  another  very  thick  mass,  lying  between  it 
and  the  granular  quartz.  Hence  it  will  be  perceived  that  these 
masses  do  not  co-ordinate  with  the  Lower  Silurian  or  Cambrian. 
1.  Quartz.  2,  2.  Limestone.  3,  3,  3.  Slates  above  and  beneath  the 
limestone.  C.  Taconic  range.  B.  Saddle  Mountain.  The  foregoing 
sections  represent  the  relations  which  these  masses  hold  to  each  other 
throughout  a  continuous  belt  extending  from  Canada  to  Georgia. 

The  Lower  Taconic  series  appears  at  Edgehill,  Pa.,  where  a 
whitish  sandstone  succeeds  and  overlies  the  gneiss.  It  is  as  usual 
interlaminated  with  slates,  in  which  talc  predominates.  Lime- 
stone succeeds  northward,  but  the  series  is  soon  concealed  beneath 
the  Permian  and  Trias.  The  Lower  Taconic  is  also  crossed  by 
the  Pottsville  Railroad,  near  Norristown.  This  lower  sandstone  is 
usually  underlaid  by  a  conglomerate,  but  at  neither  of  these  cross- 
ings is  this  important  mass  present. 

118.  Upper  Taconic  Rocks,  consist  of  numerous  beds  of  slate 
alternating  with  shales,  thin-bedded  sandstone,  some  of  which  are 
coarse  and  brecciated,  thin-bedded  bluish  limestone,  more  or  less 
cherty  and  checked  with  seams  of  white  calcareous  spar,  and  red, 
brown,  and  purple  roofing  slates. 

The  following  section  extending  from  Comstock's  landing  on  the 
Northern  Canal,  New  York,  to  North  Granville,  shows  the  relation 
of  the  upper  beds  to  the  Lower  Silurian.  The  description  of  the 
Silurian  is  in  the  ascending,  and  of  the  Upper  Taconic  in  the 
descending  order. 

119.  a.  Gneiss  :  Comstock's  landing.     1.  Potsdam  Sandstone.     2.  Calciferous 
Sandstone.     3.  Chazy  Limestone,    a.  Slates  interstratified  with  fine  grits  belong- 

g  to  the  Upper  Taconic  beds.     6.  Slates  overlying  a  mass  of  chazy  limestone. 


Fig.  58. 


TACONIC   SYSTEM. 

Fig.  59.  Fig.  60. 


85 

Fig.  61. 


Williamstown  Section. 


86 


MANUAL   OF   GEOLOGY. 


c.  Thin  Sandstones,  d.  Uneven-bedded  Slates  and  Shales,  c.  Thin-bedded 
Sparry  Limestone.  /.  Bluish  Slaty  Grits,  g.  Coarse  Calcareous  Sandstones,  i 
Gray  Sandstone,  k.  Flags  containing  marine  plants.  I.  Cherty  Sandstone,  m. 
Blue  Slates,  n.  Sparry  Limestone,  o.  Blue,  red,  and  purplish  roofing  slate  of 
East  Granville,  containing  a  single  bed  of  sparry  limestone  3£  feet  thick,  p.  Hard, 
thick  and  thin  bedded  coarse  grits,  q.  Brick  red  roofing  slate  200  feet  thick,  r. 
Slates  and  coarse  grits  alternating  with  sandstone  and  with  brecciated  beds  sepa- 
rated by  tine  bluish  slates.  These  lower  beds  are  well  exhibited  in  Grafton 
Mountain,  Rensselaer  Co.,  N.  Y.,  and  at  Bird  Mountain,  Vt.  The  red  slates  pass 
through  Granville  Four  Corners.  A  similar  section  may  be  traced  in  Wythe  Co., 
Va.,  but  the  limestones  are  much  more  largely  developed. 

At  North  Granville,  N.  Y.,  the  overlying  Lower  Silurian  lime- 
stones with  their  fossils  are  perfectly  plain  at  numerous  points. 
Fig.  61  :  1,1.  Successive  beds  of  the  Taconic  series.  2.  Calci- 
ferous  sandstone.  The  outlyers  of  Lower  Silurian  often  occupy 
troughs  in  the  slate,  and  frequently  deceive  the  observer  unless 
aware  of  the  fact ;  as  at  2,  3,  3,  3,  beds  of  calciferous  sandstone. 

Fig.  62.  120.   Tie   fossils  of 

the  lower  beds  are  limit- 
ed to  one  or  two  species 
of  corals,  and,  so  far  as 
discoveries  have  been 
made,  these  are  confined 
to  one  region,  though 
there  are  many  locali- 
ties; but  the  indivi- 
duals are  extremely 
numerous ;  these  locali- 
ties are  in  Montgomery 
Co.,  N.  C. ;  and  the 
beds  are  located  about 
midway  between  the  top 
and  bottom  of  the  quartz 
rock.  The  Palceotro- 
chis,  the  name  of  the 
fossil  in  question,  fills 
some  of  the  strata  and  is  associated  with  concretions,  some  of  which 
envelope  the  fossil  wholly  or  in  part.  The  concretions  take  the 
form  and  size  of  almonds,  and  are  usually  formed  of  concentric 
layers. 

121.  Fossils  of  the  Upper  Series. — They  consist  of  marine  plants, 
the  lowest  forms  of  animals,  as  graptolites,  and  several  species  of 
articulata.  as  trilobites  and  worm  tracks.  \ 


Palseotrochis  Minor. 


Fig.  63. 


Palaeotrochis  Major. 


Fig.  64. 


TACONIC    SYSTEM. 

Fig.  65. 


87 


Fig.  66. 


Diplograpsus  ciliatus. 
Enlarged. 


Worm  Tracks. 
Fig.  67.  Fig.  68. 


Fig.  69. 


Diplograpsus  Fo- 

liosus. 
Enlarged. 


Staurograpsns  dichotomus. 
Enlarged. 


Diplograpsus  rugosaus. 

Fig.  64.  Worm  tracks  of  the  Waterville  Slates  (Nereites 
Deweyi).  Fig.  65.  Diplograpsus  ciliatus.  Fig.  66.  Diplograpsus 
secalinus.  Fig.  67.  Diplograpsus  rugosus.  Fig.  68.  Diplograpsus 
foliosus.  Fig.  69.  Staurograpsus  dichotomus.  Fig.  70.  Para- 
doxides  asaphoides.  Fig.  71.  Atops  punctatus.  Fig.  72.  Obolus? 
Microdiscus  quadricostatus  (enlarged).  Fig.  73.  Fig.  74.  Lin- 
gula  striata.  The  two  last  are  minute  fossils. 

According  to  Barrande,  the  Paradoxides  and  Olenus  belong  to  his 
primordial  zone,  or  are  Sub-silurian  in  Bohemia.  In  this  respect 
our  paradoxides  are  also  Sub-silurian  j  and  hence  it  has  been  shown 


MANUAL   OF    GEOLOGY. 
Fig.  70. 


Fig.  71. 


Paradoxides  macrocephalus. 

Fig.  72.  Fig.  73.  Fig.  74. 


Mic rod i sous  Qua- 
dricostatus. 
Enlarged. 

75. 


Unconformity  of  the  calciferous  sandstone  a,  with 
the  Taconic  slates,  6. 


TACONIC   SYSTEM.  89 

that  the  primordial  zone  in  Bohemia  is  in  co-ordination  with  the 
upper  series  of  the  Taconic  rocks. 

The  range  of  country  through  which  this  series  passes  is  the  western  face  of 
the  Green  Mountains,  extending  from  Canada  to  Georgia.  These  rocks  cross  the 
Blue  Ridge  at  Harper's  Ferry,  or  in  its  vicinity.  They  occupy  also  a  range  of 
hills  or  mountains,  east  of  Wytheville,  Va.,  extending  westward  to  the  immediate 
vicinity  of  the  Queen's  Knob,  where  they  face  unproductive  coal  measures.  The 
series  also  passes  along  the  eastern  flanks  of  the  Green  Mountains  and  Blue  Ridge, 
passing  through  the  eastern  part  of  Virginia  and  North  Carolina,  and  onwards 
into  Alabama.  Upon  this  belt  are  numerous  gold,  copper,  and  iron  mines  in 
veins  and  beds. 

The  same  series  occur  upon  Lake  Huron  and  Lake  Superior  district,  and  also 
in  Arkansas  in  the  vicinity  of  the  hot  springs.  This  series  is  developed  on  the 
Ocoee  river  in  heavy  beds  of  conglomerates,  slates,  and  grits.  Prof.  Safford 
refers  some  of  the  rocks  upon  the  French  Broad  in  North  Carolina  and  Tennessee, 
the  rocks  forming  the  ranges  in  Sevier  County,  to  an  Azoic  or  Sub-silurian  sys- 
tem. Prof.  H.  D.  Rogers  distinctly  defines  a  zone  of  sediments  which  he  regards 
as  semi-metamorphic,  and  which  occupies  a  broad  belt  south  of  the  limestone 
valleys  of  the  Conestoga  and  Codorus  streams  in  Lancaster  and  York  counties. 
This  zone,  however,  belongs  to  the  Lower  Taconic  series,  if  his  description  can 
be  relied  upon.  Prof.  R.  applies  the  term  Azoic  to  these  Sub-silurian  deposits, 
a  term  which  is  inadmissible  when  applied  to  sediments.*" 

The  Taconic  series,  especially  the  lower  division,  furnishes  many  fine  exhibi- 
tions of  displacements  and  inversions  of  strata.  Of  the  latter,  Stone  Hill,  an  emi- 
nence south  of  Williams  College,  is  an  interesting  example.  The  hill  is  about 
500  feet  above  the  Hoosick  river.  Its  strata  dip  to  the  south-east ;  but  the 
oldest  layers  repose  upon  the  newest,  so  far  as  those  composing  the  hill  are  con- 
cerned; or,  in  other  words,  they  have  been  forced  so  far  over  that  the  original 
bottom  beds  occupy  the  uppermost  position.  Many  contorted  strata  occur,  exhi- 
biting remarkable  cases  of  lateral  pressure. 

*  See  Note  A,  page  280. 


Fig.  76. 


CHAPTER  XII. 

SILURIAN  SYSTEM — GENERAL  STATEMENT  OP  FACTS  RELATIVE 
TO  ITS  EPOCH — DESCRIPTION  AND  DIVISION  OF  THE  MEMBERS 
COMPOSING  THE  SYSTEM,  ITS  FOSSILS,  ETC. 

122.  THE  Silurian  system,  which  fills  so  large  a  volume  in  the 
geologic  history  of  Europe,  seems  to  be  still  more  full  and  complete 
in  America.  It  extends  from  Canada  on  the  north,  to  Alabama  on 
the  south.  The  Adirondacks,  which  bulge  up,  and  form,  as  it 
were,  a  great  but  irregular  dome,  throw  off  the  oldest  sediments 
of  the  system  in  all  directions,  but  more  especially  in  two :  one 
towards  the  north-east,  and  the  other  towards  the  south-west.  The 
dip  of  the  rocks,  on  the  north-east  side,  indicates  the  existence  of 
a  great  and  widely  spread-out  basin  in  this  direction,  which  might 
be  called  the  Lawrentine  Basin  of  the  system.  Following  the 
dip  to  the  south-west,  the  indications  are  equally  clear  that,  in  this 
direction,  too,  there  is  another  basin  of  a  vast  extent  having  its 
south-eastern  base  in  the  Appalachian  Mountains,  and,  hence, 
might  be  called  the  Appalachian  Basin  of  the  Silurian  system. 
These  basins  are  separated  by  an  anticlinal  axis,  which  is  very 
clearly  marked  by  the  Highlands  of  Northern  New  York.  A  rough 
measurement  through  both  basins,  over  this  anticlinal,  gives  us  at 
least  a  distance  of  twenty  degrees  of  latitude.  Following  the  base 
of  this  system  from  the  northern  extremity  of  Lake  Champlain  to 
the  St.  Lawrence,  and  then  tracing  its  course  along  the  irregular 
borders  of  the  great  lakes  to  the  waters  of  the  Mississippi  above 
the  Falls  of  St.  Anthony,  we  shall  find  its  extent,  in  this  direction, 
not  less  than  1500  miles. 

A  peculiar  feature  belongs  to  both  basins,  especially  the  south- 
western one.  It  consists  in  the  remarkable  regularity  of  the  suc- 
cession of  its  strata.  These  wide  areas  are  scarcely  broken  by 
igneous  injections;  and,  hence,  the  regular  succession  of  strata 
is  rarely  interrupted  or  displaced  by  outbursts  of  the  pyro-crys- 
talline  rocks. 

This  freedom  from  breaks  and  interpolated  igneous  masses  had 

(90) 


SILURIAN   SYSTEM.  91 

aD  important  bearing  upon  the  regularity  of  the  succession  of  its 
organic  stages ;  and,  hence,  secured  the  most  favorable  condition 
for  the  preservation  of  life;  and  to  this  we  may  attribute  the  per- 
fect representation  of  these  stages  during  the  whole  Silurian  period. 
The  two  facts  seem  to  harmonize  so  well  that  they  may  be  related 
to  each  other  as  cause  and  effect.  From  the  foregoing  it  will  pro- 
bably follow,  that  the  time,  when  important  species  were  created, 
may  be  more  exactly  determined  ;  and  so,  also,  may  the  time  of  their 
extinction  become  a  matter  more  easily  settled,  than  if  the  areas, 
over  which  they  are  spread,  were  broken  and  dislocated  by  frequent 
eruptions.  The  history  of  the  Palaeozoic  period  will,  therefore,  be 
more  complete,  and  at  the  same  time  more  interesting  for  its  mani- 
fold developments  of  organic  beings.  It  is  in  this  system  that  life 
begins  to  assume  a  supremacy  over  dead  matter.  All  the  great 
branches  representing  animal  life  appear  in  this  period,  though  not 
in  perfection.  It  is  mainly  the  lower  ranks  of  each  branch  respec- 
tively, which  appear  in  this  system.  It  might  be  called  the  Pro- 
phetic system. 

It  is  all  important  that  the  student  should  be  informed,  that, 
with  respect  to  American  systems  of  rocks,  we  have,  as  yet,  been 
unable  to  make  out  that  their  subordinate  parts  have,  in  all 
instances,  their  synchronisms  in  the  European  systems  of  the  same 
name.  We  can  identify  certain  subdivisions;  but  there  are  many 
breaks  between  the  subdivisions,  which  have  not  as  yet  been 
shown  to  be  synchronous.  It  will  be  well  to  prove,  if  possible, 
that  our  formations  are  parallel  with  well-known  European  ones ; 
but  nothing  is  gained  by  assuming  it  to  be  the  fact  in  the  absence 
of  proof.  The  American  continent  has  its  own  history ;  and  we 
have  reason  to  believe  that,  in  many  respects,  especially  in  its 
details,  we  shall  find  it  to  differ  from  that  of  Europe.  Hence,  it 
should  be  worked  out  independently  of  foreign  bias.  It  is,  no  doubt, 
true,  that,  as  great  masses,  there  is  a  close  connection  in  the  Ame- 
rican and  European  divisions ;  and,  in  many  instances,  it  exists  in 
the  subordinate  parts,  and  some  of  the  breaks  are  synchronous  ; 
others  are  not  yet  proved  to  be  so. 

123.  -Subdivisions  of  the  Silurian  System. — The  Silurian  system 
may  be  divided  into  Lower,  Middle,  and  Upper:  Lower  Silurian, 
Champlain  Group,  or  Cambrian.  The  oldest  member  of  this  divi- 
sion is  a  sandstone  of  a  red,  gray,  or  chocolate  color,  and  sometimes 
white.  It  is  the  Potsdam  sandstone  of  the  New  York  survey.  The 


92 


MANUAL   OF   GEOLOGY. 


Lingula  antiqua. 


Fig.  77.  bottom   is  a  conglomerate.     Its  greatest 

thickness  is  about  800  feet.  It  contains 
a  lingula,  fig.  77,  and  two  or  more  species 
of  trilobites.  The  next  in  succession  is 
the  Calciferous  Sandstone,  being  a  mix- 
ture of  carbonate  of  lime  and  fine  grains 
of  quartz.  In  color  it  varies,  but  usually 
is  of  some  shade  of  gray.  Weathers  to  a 
drab  color.  It  is  sometimes  oolitic,  as  at 
Chazy,  or  concretionary,  as  at  Little  Falls. 
Its  fracture  is  uneven  and  sparkling.  The  middle  and  upper  parts 
are  cherty,  and  contain  much  magnesia,  and  has  been  called  magne- 
sian  limestone ;  it  contains  quartz  crystals  and  solidified  bitumen ; 
the  latter  is  often  enclosed  in  limpid  quartz.  Fig.  78  represents 
some  of  the  fossils  of  this  rock.  In  the  absence  of  the  Potsdam 
sandstone,  as  at  Little  Falls,  N.  Y.,  it  rests  upon  the  pyre-crystalline 
rocks  or  the  Taconic  system.  It  is  more  extensive  than  the  former 
rock.  At  Chazy,  N.  Y.,  it  is  highly  fossiliferous. 

124.  The  Chazy  limestone  succeeds  the  calciferous  sandstone.  It 
is  a  dark-colored  rock,  and  abounds  in  corals.  But  its  most  im- 
portant organic  remains  are  gasteropods,  particularly  the  Macleurea, 
fig.  79.  This  name,  however,  has  been  changed  into  Straparollus 
by  D'Orbigny.  It  was  first  called  Maclurites  magnus  by  Le  Seur 
We  have  followed  D'Orbigny,  and  hence  this  remarkable  fossil  takes 
the  name  of  Straparollus  rnagnus.  It  is  quite  common  at  Chazy 
and  at  Essex,  N.  Y.  It  is  equally  common  in  the  same  rock  in 
Wythe  Co.,  Va. 

A  coral  is  also  quite  common  :  the  Columnaria  alveolata,  Fig.  80. 
The  Birds'  Eye  Limestone,  which  overlies  the  Chazy,  is  a  close- 
grained,  compact  limestone,  and  breaks  with  a  conchoidal  fracture ; 
it  is  rarely,  if  ever,  over  30  feet  thick.  In  Canada  its  color  is 
quite  light,  and  it  has  been  used  for  lithographic  drawings.  The 
fossils  of  the  Trenton  appear  in  the  rock.  A  very  singular  fossil, 
called  by  Mr.  Conrad  Fucoides  demissus,  fig.  81,  seems  to  cha- 
racterize the  limestone.  Its  name  has  been  changed  to  Phytopsis 
tubulosum  by  Hall.  Several  cephalopods  occur  in  this  rock :  the 
most  common  is  the  Orthoceras  multicameratum,  fig.  82. 

The  Bird's  Eye  is  a  very  compact  and  brittle  rock,  and  breaks 
with  a  conchoidal  fracture.  It  presents  numerous  crystalline 


SILURIAN   SYSTEM. 
Fig.  78. 


93 


1.  Scalites  angulatus.    2.  Straparollus  labiatus.    3.  Straparollus  Striatus.    4.  Bellerophoix  •* 
satinus.    5.  Cast  of  orthis.    6.  Diacina. 


94 


MANUAL   OF    GEOLOGY. 
Fig.  79. 


Straparollus  magnus. 


Fig.  80. 


Columnaria  alveolata. 


points,  which  gives  the  surface  the 
peculiar  appearance  from  which  its 
name  was  derived. 

The  Black  River  limestone,  or  Isle 
La  Motte  marble,  is  the  least  com- 
mon ;  but,  at  Watertown,  N.  Y.,  and 
Isle  La  Motte,  on  Lake  Charnplain, 
it  is  present.  It  is  black,  and  is  ex- 
tremely fine-grained.  It  is  between 
seven  and  fifteen  feet  thick,  and  it 
forms  a  fine  black  marble. 

125.  The  Trenton  limestone  is  either  black  or  gray.  The  lower 
part  is  usually  black,  and  when  well  developed,  as  at  Watertown, 
N.  Y.,  it  becomes  gray  and  sub-crystalline.  These  divisions  of  this 
limestone  were  made  on  the  ground  that  each  mass  contains  pe- 
culiar fossils,  and  which  are  confined  to  each  respectively.  This  is 
found  untrue.  The  thickness  of  the  Trenton  limestone  is  about 
400  feet.  The  total  thickness  of  the  four  masses  of  limestone, 
as  given  by  Mr.  Logan,  near  Montreal,  is  1200  feet,  but  at  the 
Manitoulin  Islands,  or  westward,  they  diminish  in  thickness,  and 
scarcely  exceed  300  feet.  The  Trenton  limestone  is  variable  as  to 
its  lithological  character.  At  certain  localities,  as  at  Chazy  and 


SILURIAN    SYSTEM. 
Fig.  81. 


95 


Phytopsis  tubulosum. 
Fig.  82. 


At 


Orthoceras  multicamerata. 

Montreal,  it  has  intercalated  beds  of  black  bituminous  slate, 
other  places  it  is  mainly  a  solid  limestone. 

126.  The  fossils  are  abundant  in  all  these  rocks,  especially  the 
Trenton  limestone.  Some  of  the  characteristic  forms  are  repre- 
sented in  the  following  cuts. 


Fig.  83. 
Ventral  valve. 


Fig.  84. 
Dorsal  valve. 


Strophomena  alternistriata. 


96 


MANUAL   OF   GEOLOGY. 

Fig.  85. 
CEPHALOPODA. 


Trocholites  ammonius. 


SILURIAN    SYSTEM. 

Fig.  86. 
CEPHALOPODA. 


97 


Lituites  undatus. 
Side  and  Back  Views. 


98 


MANUAJL   OP   GEOLOGY. 

Fig.  87. 
GASTEROPODA. 


4.  Cyrtolites  filosum. 

5.  Bellerophon  punotifronf. 


Pleurotomaria  lenticularis. 


SILURIAN   SYSTEM. 


99 


Fig.  88. 
BRACHIOPODA  OF  THE  TRENTON  LIMESTONE. 


ia.  Surface  of  T.  terminalis.  Leptsena  seric«a 


Lingula  papillosa.        Discina  truncata. 


Sections  of  the  Stropliomena. 


Ambonychia  orbicularis. 


Triple sia  exta 


Strophomena  sinuata. 


Strophoraena  alternate. 


Orthis  pectinella. 


100 


MANUAL   OP   GEOLOGY. 


Fig.  89. 
CRUSTACEA. 


Triarthrua  Beckii. 


SILURIAN    SYSTEM. 


101 


The  Utica   slate,  which  is   a  black   and 


Fig.  91. 


tender  rock,  reposes  upon  the  Trenton  lime-    FOSSILS  OF  UTICA 
stone.     It  is  often  bituminous.     Its  greatest  SLATE, 

thickness  is  about  75  feet.  It  does  not  occur 
in  a  condition  of  a  roofing  slate.  To  this 
slate  the  Lorrain  shales  and  sandstone  suc- 
ceed. The  line  of  junction  is  obscure,  and 
the  annexed  fossils  occur  in  both  series  of 
beds.  These  are  thin-bedded  shaly  deposits 
with  a  few  calcareous  beds  interposed.  'The 
lowest  beds  are  quite  thin,  and  alternate  with 
slate.  As  we  ascend  in  the  series,  the  sili- 
cious  or  sandy  beds  become  thicker,  and  the  L  Triarthms  Becwi.  • 
formation  finally  terminates  in  a  thick-bedded 
gray  sandstone  in  New  York  and  Canada. 
In  the  West,  or  in  the  vicinity  of  Cincin- 
nati, the  whole  formation  is  much  more  cal- 
careous, and  is  there  known  as  the  Blue 
Limestone.  It  is  fossiliferous,  especially  in 
the  West. 

127.  If  we  now  turn  our  attention  to  the 
south-west,  or  Wytheville,  and  the  head 
waters  of  the  Clinch  and  Holstein,  Virginia, 
we  find  these  masses  to  wear  a  different 
phase  from  what  they  do  in  New  York  and 
Canada. 

Thus,  the  Potsdam  sandstone  has  an  open 
texture,  and  alternates  twice  with  the  Calci- 
ferous  sandstone ;  the  latter,  in  many  places, 
consists  almost  entirely  of  chert.  The 
Trenton  limestone  is  white  and  crystalline, 
though  loaded  with  organic  remains,  and 
is  entirely  destitute  of  bitumen.  The  Lorrain  shales  and  sandstones, 
in  the  ascending  order,  consist  of,  first,  a  reddish,  mottled  sandstone, 
pebbly  at  bottom,  but  becomes  a  sandy  marl,  and  contains  fossili- 
ferous bands,  which  serve  to  identify  it  with  the  rock  in  Northern 
New  York.  It  is  about  100  feet  thick.  Above  this  mass  there 
is  a  calcareous  shale,  which  finally  becomes  a  thin-bedded  lime- 
stone, and,  still  higher,  there  are  olive-green,  thin-bedded  sand- 
stones and  marls,  containing  Pterinea  carinata.  These  beds  are 
equivalent  to  the  thick-bedded  sandstones  of  Oneida,  Jefferson 
9* 


102 


MANUAL   OP   GEOLOGY. 


Fig.  92. 
FOSSILS  OF  THE  LORRAIN  SHALES. 


1.  Murchisonia  gracilis. 

2.  Avicula  demissa. 

3.  Orthis  testudinaria. 

4.  Modiolopsis  roodiolaris. 

5.  Orthis  crispata. 

6.  Pedicloof  cystidean. 

7.  Heterocrinus. 

8.  Porcelia  ornata. 


SILURIAN   SYSTEM. 


103 


county,  New  York,  and  the  Blue  limestone  in  part  of  the  Western 
States. 

128.  Oneida  Conglomerate. — Above,  and  resting  upon  the  last 
member  of  the  foregoing  series,  is  the  Oneida  conglomerate,  or  Sha- 
wangunk  grits.  It  is  a  hard  gray  rock  made  principally  of  pebbles. 
Whether  it  should  be  considered  as  holding  a  connection  with  the 
foregoing  rocks,  or  be  regarded  as  the  inferior  member  of  the 
Middle  Silurian,  is  not  well  determined.  In  one  point  of  view,  it 
is  an  important  rock,  insomuch  as  it  indicates  a  line  of  demarkation 
between  the  Lower  and  Middle  Silurian  rocks.  It  is  probable,  that 
it  belongs  to  the  Middle  Silurian. 

Fig.  93. 


Trinucleus  Caractaci? 


Conularia  Hudsonia.     Enlarged. 


Receptaculites  belongs  to  the  sub-class  Bryozoa,  and  appears  to 
be  a  rare  fossil.  The  Conularia  belongs  to  the  class  Pteropoda,  and 
is  also  a  rare  species  in  the  Lorrain  shales. 

The  Lower  Silurian,  in  Northern  New  York,  is  rarely  disturbed 
by  dykes  or  intruded  rocks.  In  Jefferson  and  St.  Lawrence  coun- 
ties, the  Potsdam  Sandstone  is  tilted  up,  and  the  specular  oxide  of 
iron,  in  those  cases,  often  occupies  a  position  between  the  Potsdam 
and  the  primary  rocks  beneath. 

On  the  Champlain  side  near  the  village  of  Essex,  and,  indeed, 
in  many  other  places,  trap-dykes  and  porphyritic  rocks  cut  through 
the  lower  limestones. 

Near  Essex,  the  Calciferous  sandstone  is  raised  upward,  so  as  to 


104 


MANUAL   OP   GEOLOGY. 
Fig.  94. 


b  a  ft 

Disturbed  Strata  in  the  Lower  Silurian,  Essex  Co.,  N.  Y. 

be  on  a  level  with  the  Utica  slate,  as  represented  in  Fig.  94.  a, 
calciferous  sandstone;  J,  line  of  junction  with  the  slate;  c,  thin 
dykes  traversing  the  slate  ;  b,  slate  thrown  into  undulations.  The 
foregoing  represents  a  series  of  phenomena  which  are  common  in 
districts  disturbed  by  faults  and  igneous  injections. 

129.  Middle  Series  of  the  Silurian  or  Ontario  Division  of  the 
System. — It    comprehends  the  Oneida  Conglomerate  or  Shawan- 
gunk  Grits,  the  Medina  Sandstone.  Clinton,  and  Niagara  Groups. 
In  the  West,  this  division  is  called  Cliff  Limestone,  not  including 
the  Oneida  Conglomerate  and  Medina  Sandstone. 

The  Medina  Sandstone  is  an  argillaceous  mottled  sandstone,  in 
part,  and  is  easily  destructible  by  atmospheric  agencies ;  hence,  it 
rarely  appears  in  sharp  well-defined  outcrops.  The  upper  part 
consists  of  firm  and  thin  beds  of  light-reddish  sandstone,  with  a 
texture  sufficiently  close  to  preserve,  in  perfection,  ripple  marks 
and  wave  lines.  There  is  also  a  coarse  gray  band  at  the  top  in  the 
gorges  of  the  Genesee  river,  which  is  somewhat  pebbly.  The 
rock  is  also  mottled  with  light-green  patches  like  the  New  Red 
or  Triassic  Sandstone.  It  is  the  lowest  rock  which  is  known  to 
furnish  brine-springs.  They  are  not,  however,  pure  enough,  nor 
do  they  furnish  saline  matter  in  sufficient  abundance,  to  be  em- 
ployed economically  in  the  manufacture  of  salt. 

It  forms  a  border  along  the  shore  of  Lake  Ontario  and  the 
crests  of  the  Alleghenies  in  Virginia. 

Fossils  of  the  Medina  Sandstone  :  The  most  common  fossil 
is  the  Arthopycus  Harlani,  fig.  95,  a  marine  vegetable,  and  formerly 
described  as  the  Fucoides  Harlani.  It  is  common  to  New  York 
and  the  Virginia  series.  The  Lingula  cuneata  (Fig.  96)  is  also 
a  common  fossil. 

130.  Clinton  Group. — It  consists  of  many  beds  comprising  gray 
and  brown  sandstones,  green  shale,  slate,  conglomerates,  limestones, 


SILURIAN    SYSTEM. 


105 


Fig.  95. 


J 


Arthopycus  harlani. 


106  MANUAL   OF   GEOLOGY, 

Fig.  96. 


Lingula  cuneata. 

and  oolitic  iron  ore.     It  has  been   called  the  Protean  Group  on 
account  of  the  heterogeneous  assemblage  of  materials. 

In  Warren,  Herkimer  County,  New  York,  the  following  section 
occurs : 

1.  Bluish  Gritty  Shale,  1  foot.  2.  Gray  Sandstone,  2  feet.  3.  Blue  Gritty 
Shale,  1  foot.  4.  Gray  Sandstone,  4  feet.  5.  Pebbly  Beds,  2  feet.  6.  Blue 
Shale,  i  foot.  7.  Grayish  Shale,  i  foot.  8.  Iron  Gray  Sandstone,  £  foot.  9. 
Thin-bedded  Sa-ndstone,  1  foot.  10.  Fine  Pebbly  Conglomerates,  8  feet.  11. 
Soft  Brown  Sandstone,  2  feet.  12.  Dark-colored  Shale,  3  feet. 

In  the  debris  are  fragments  of  iron  ore.    The  bed  is  concealed. 

This  series  rests  on  the  Oneida  Conglomerate,  as  the  Medina 
sandstone  does  not  extend  so  far  east.  On  Steel's  Creek,  at  Mohawk, 
the  formation  attains  its  maximum  thickness,  which  is  about  70 
feet.  At  the  West,  the  formation  presents  a  different  aspect. 

At  the  Lower  Falls  of  the  Genesee,  reckoning  in  the  ascending 
order,  we  have  obtained  the  following  section  : 

1.  Gray  Band  of  the  Medina  Sandstone.  2.  A  Tender  Fissile  Green  Slate. — 
15  feet.  3.  Lower  Bed  of  Oolitic  Iron  Ore. — 14  inches.  4.  Limestone  with  Pen- 
tamerus  oblongus. — 14  feet.  5.  Green  Shale,  like  No.  2. — 24  feet.  6.  Impure 
Limestone  and  Shale.— 18  feet. 

To  the  east,  this  group  is  sandy,  or  made  up  of  grits,  while  to 
the  west  it  becomes  calcareous.  At  Anticosti,  the  Clinton  group 
is  well-developed,  or  the  rocks  consist  in  part  of  this  group. 

Walker's  Mt.,  on  the  head  waters  of  the  Clinch  River,  in  South- 
Western  Virginia,  and  the  subordinate  ranges  of  this  region,  are 
composed  of  the  rocks  of  this  group.  The  Medina  sandstone  often 
forms  their  summits. 


SILURIAN   SYSTEM. 

Fig.  97. 
FOSSILS  OF  THE  CLI-NTON  GROUP. 


107 


1.  Rusophycus  bilobatus.    2.  Hemicripturus.     3.  Crinoidal  Joint.    4.  Lingula  oblonga.    5. 
Strophomena  depressa. 


Pentamera3  nobilis,  E. 


108 


MANUAL   OP   GEOLOGY. 
Fig.  98. 


1.   Atrypa  imbricata.    S5.    Atrypa.    3,  4,  4a. 
n  ynconella  cuneata.       6.  Euomphalus  hemisph  ricus. 


8.  Illsenus  barriensis. 


SILURIAN    SYSTEM. 


109 


Fig.  99. 
BRACHIOPODA  OF  THE  NIAGARA  GROUP. 


1.  Spirifer  Niagarensis.    2.  Spirifer  radiatus.    3.   Spirifer  staminea.    4.  Spirifer  decemplicatui. 
5.  Orthis  flabellum.   6.  Orthis  canalis.    7.  Orthis  hybrida.    8.  Spirifer  finuatus. 


10 


110 


MANUAL  OP  GEOLOGY. 

Fig.  100. 
CRINOIDS  OF  THE  NIAGARA  GROUP. 


Ichthyocriuus  laevfo. 


lyecanocrinus  macropetalua. 


SILURIAN    SYSTEM. 


Ill 


Fig.  101. 
CORALS  OF  THE  NIAGARA  GROUP. 


1,  2,  3.  Halycites  catenularia. 

The  Halycites  (Catenipora)  catenularia  is  probably  never  found  above  or  below 
the  Clinton  and  Niagara  groups,  and  is  hence  a  very  characteristic  fossil. 


112  MANUAL   OF   GEOLOGY. 

Niagara  Group. — It  consists  mainly  of  three  members :  Nia- 
gara shale,  Niagara  limestone,  and  Coralline  limestone.  The  first 
is  a  tender,  bluish  rock,  which  whitens  on  exposure  to  the  weather. 
The  second  is  often  a  dark-colored  massive  limestone,  and  frequently 
bituminous.  It  may  be  described  in  the  following  section : — 

1.  Beds  of  gray  silicious  limestone,  often  hydraulic. 

2.  Thin  beds  of  shaly  limestone,  sometimes  concretionary. 

3.  Thick  and  thin  beds  of  limestone. 

4.  A  cherty  and  bituminous  limestone;  gray  or  brown,  -with  numerous  geodes 
of  calcspar,  gypsum,  strontian,  or  brown  spar. 

The  limestone  is  often  crystalline  and  sparkling,  as  at  Lockport. 
The  eastern  limit  of  this  limestone  is  Swift  Creek  in  Oneida  Co.,  where  it  is 
curiously  concretionary,  and  only  about  four  feet  thick. 

Thickness  of  the  Ontario  Division  in  New  York. 

The  Medina  Sandstone  is 350  feet  tnick. 

Clinton  Group 80          " 

Niagara  Shale          .         .         .         .         .         .         .100          " 

Niagara  Limestone          .        .        .        .        .        .160         " 


131.  The    Coralline  Limestone,   in    the    Helderberg,  rests   on 
green  shale,  which  is,  no  doubt,  the  representative  of  the  Clinton 
group.      It  is  scarcely  probable  the   equivalent   of  the   Niagara 
limestone,  as  the  rock  contains  fossils  similar  to  those  which  cha- 
racterize the  succeeding  masses. 

132.  General  Distribution. — The  Ontario  division  is  quite  ex- 
tensive in  the  United  States.     In  New  York  it  forms  a  narrow 
belt  along  the   south  shore  of  Lake  Ontario.     It  dips   south  or 
south-west.     In  Pennsylvania  it  occupies  a  narrow  belt  along  the 
north-western  base  of  the  Kittatinny  Mountain.     It  extends  from 
Perry  county,  nearly  to  the  Delaware  Water  Gap.     The  Medina 
sandstone,  accompanied  by  the  Clinton  group,  with  its  iron  ores, 
form  the   summits  or  belts  of  all   the  ridges  west-south-west  of 
Wytheville,  Virginia.    The  top  of  Walker's  Mountain,  about  twelve 
miles  from  Wytheville,  is  probably  carboniferous ;  but,  immediately 
beneath,  the  Medina  sandstone,  becomes  a  very  prominent  rock,  and 
caps  the  ridge  on  Shannon's  side  of  this  mountain.     In  a  descend- 
ing order,  we  find  the  following  succession  : — 


SILURIAN    SYSTEM.  113 

1.  Clinton  group,  and  an  imperfectly  developed  Niagara  limestone,  which  is 
very  cherty.  2.  Medina  sandstone.  3.  Upper  Lorrain  shalo,  slates,  and  sand- 
stones. 4.  Calcareous  beds.  5.  Lower  Lorrain  beds,  consisting  of  green  shale, 
brick  red  massive  slates,  and  very  tough;  gray  sandstones  and  conglomerate. 
6.  White  Trenton  limestone.  7.  Bird's  Eye  and  Chazy  limestone.  8.  Calciferous 
sandstone  with  drab-colored  layers.  9.  Gray  sandstone  (Potsdam).  This  divi- 
sion of  the  Silurian  occupies,  therefore,  the  summits  or  ridges  of  the  high  ranges 
about  the  head  waters  of  the  Clinch  and  Holstein. 

133.  Helderlerg,  or  Upper  Division  of  the  Silurian  System. — 
In  this  series  we  place  the  Onondaga  salt  and  plaster  group.     The 
Manlius    Water    limestone,    Pentamerus    limestone,    green    shaly 
limestone,  Encrinal  limestone,  and  Upper  Pentamerus  limestone. 

134.  The  Onondaga  Salt  Group  consists  of  soft,  red,  and  mottled 
argillaceous  shales,  which,  at  many  places,  pass  into  a  drab  color. 
The  lower  part  is  a  bluish  marl,  with  bands  of  red  and  brown  ;  above, 
it  becomes  calcareous,  and  contains  seams  of  gypsum,  and  at  its 
termination  in  Onondaga  Co.,  it  becomes  gray  or  drab-colored  lime- 
stone, which  is  magnesian.    The  contrast  between  this  great  deposit 
of  soft  shales  and  marls  is  very  great,  when  compared  with  the 
Niagara  limestone  on  which  it  rests.     The  softer  portions  contain 
hopper  form  cavities,  or  moulds  which  appear  to  have  contained 
crystallized  rock  salt. 

135.  Extent. — Westward  it  extends   into  Canada :    an  obscure 
mass  of  rock,  about  20   feet   thick,  in  the   Helderberg   and   at 
Schoharie,  represent  the  whole  formation.     It  is  not  generally  dis- 
tributed, and  should  be  regarded  rather  as  a  local,  though  by  no 
means  an  unimportant  formation.    It  furnishes  from  its  middle  beds 
a  large  quantity  of  plaster,  and  from  the  wells,  which  are  usually 
sunk  in  drift,  brine  springs,  which  give  a  large  revenue  to  the  state 
of  New  York. 

Fig.  102. 
WATER  LIME  FOSSILS. 


1.  Spirifer  plicatus.    2.  Avicula  mgosa.    3.  Tentaculites  omatns.   4.  Holopea  antiqua.   5.  Atrypa 
lulcata.    6.  Leperditia  alta. 


114 


MANUAL   OF   GEOLOGY. 


136.  Water  Lime,  or  Manlius  Water  Lime  Group. — It  consists 
of  thin-bedded  drab,  or  gray  limestones.    The  upper  beds  are  thick, 
and  are  employed  for  the  cement  so  well  known  in  market. 

The  Pentamerus  limestone  succeeds,  and  it  is  almost  always  con- 
cretionary, at  least  in  part.  It  is  gray  and  thick-bedded. 

Both  the  foregoing  masses  are  well  developed  at  the  base  of  the 
Helderberg,  and  also  in  the  valley  of  the  Rondout,  and  Becraft's 
Mountain,  east  of  Hudson. 

Green  shaly  limestone  is  an  argillaceous  limestone,  and  many 
of  its  layers  are  very  thin :  rarely  crystalline.  It  weathers  from 
a  bluish  color  to  a  drab.  It  may  be  examined  at  Becraft's  Mountain, 
and  on  a  line  of  outcrop  from  Kingston  Point  to  Coeymans  at  the 
Helderberg,  Schoharie,  and  west  a  short  distance  beyond  Cherry 
Valley  in  New  York.  It  is  about  thirty  feet  thick.  It  is  remark- 
ably rich  in  fossils,  but  is  not  widely  distributed. 

137.  Encrinal  Limestone. — It  is  a  semi-crystalline  rock,  and  is 
made  up  in  great  measure  of  peculiar  crinoidal  remains.    It  is  nearly 
a  pure  limestone,  and  polishes  well,  and  hence  it  often  furnishes 
fine  slabs    for  mantel-pieces,  tables,  &c.     It  is   25   feet  thick  at 
Becraft's  Mountain,  and  but  scarcely  exceeds  10  at  New  Scotland 
in  the  Helderberg. 

Fig.  103. 
BRACHIOPODA  OF  THE  UPPER  SILURIAN. 


Rhyconella  formosa. 
a,  6.  Dorsal  view.    c.  Ventral  view,   d,  e.  Edge  view 


SILURIAN    SYSTEM. 

'  Fig.  104. 
BRACHIOPODA  OP  THE  UPPER  SILURIAN. 


115 


1,  2.  Strophomena  Woolworthanau 


Strophonfeaa  Headlcyana. 


116 


MANUAL   OP   GEOLOGY. 


Fig.  105. 
BRACHIOPODA  OF  THE  GREEN  SHALY  LIMESTONE. 


Side  view. 

Trent  view. 
1, 2, 3,  4.  Merista  arcuata.       4,  5,  6, 7,  8,  9.  Merista  Isevis.       10, 11.  Merista  princepf. 


SILURIAN    SYSTEM. 

Fig.  106. 
BRACHIOPODA  OF  THE  UPPER  SILURIAN. 


117 


1,  2,  3,  4.  Meristabella.     5.  Merista  princeps.     6,  6  a,  6  b.  Rhynconella  mutabilis.   .  7.  Orthis. 
8,  9,  Rhynconella  mutabilis.     9  a.  Rhyncoaella  ventricosa. 

The  genus  Merista  is  closely  allied  to  the  Terebratula :  its  beak 
is  imperforate.  Their  shells  are  ovate,  sometimes  transversely  so, 
and  are  ornamented  by  parallel  circular  lines.  The  mesial  fold  is 
much  less  prominent  than  in  the  Rhynconella.  The  shell  is  thin, 
often  ventricose.  The  beak  is  rather  prominent  and  incurved. 


118 


MANUAL  OF  GEOLOGY. 


Fig.  107. 

BRACHIOPODA  OF  THE  UPPER  SILURIAN. 

2 


1,  2,  3,  4,  5,  6,  7.  Etonia  medialis.    8.  9.  Rhynconella  transversa.     10.  Rhynconella  aoutiplicata. 
11,  12, 13, 14.  Rhyneonella  altiplioata. 

The  Etonia  medialis  was  formerly  the  Atrypa  medialis  of  Van- 
uxem,  figured  in  the  New  York  Geological  Reports.  The  internal 
structure  of  the  fossil  is  found  to  differ  from  the  genus  Atrypa ; 
and  hence  the  necessity  of  changing  the  name  of  the  fossil.  The 
ventral  valve  is  also  flat,  and  the  hinge  is  indicated  by  a  straight 
line. 


SILURIAN    SYSTEM. 

Fig.  108. 
BKACHIOPODA  OF  THE  UPPER  SILURIAN. 


119 


1.  Rhynconella  abrupta.    2, 3.  Bhyncouella  vellicata.    4  Pentamerua  galeatus.     5.  Pentamerua 
Vernuijli. 

The  Rhynconella  is  marked  externally  by  a  strong  mesial  fold,  and 
the  shell  is  ribbed  and  often  highly  ornamented  by  numerous  pli- 
cations of  the  ribs.  The  sinus  is  often  deep ;  and  one  valve  appears 
always  to  extend  itself  around  the  base  and  to  interlock  upon  the 
opposite  side. 

They  appear  to  be  closely  united  both  to  the  Terebratula  and  the 
Atrypa. 

The  Pentamerus  galeatus  (fig.  4),  is  the  characteristic  fossil  of 
the  lower  Pentamerus  limestone. 


120 


MANUAL   OF   GEOLOGY. 


Fig.  109. 
BRACHIOPODA  OF  THE  UPPER  SILURIAN. 


1,  I  a,  1  b,  1  c.  Rhynconella  mutabilis.    2.  Rhynconella  semiplicata.    3.  Rensselaeria  sequicoa- 
tata.    4,  4  a.  Rhynconella  nobilis.    4,  4  a,  4  b,  Rhynconella  nobilis. 


SILURIAN   SYSTEM. 
Fig.  110. 


121 


Platyceras  plicatum. 
1.  Anterior  side.    2.  Left  side.    3.  Posterior  side.    4.  Folds  of  the  anterior  side. 

11 


122  MANUAL  OF  GEOLOGY. 

Fig.  111. 
CRUSTACEANS  OF  THE  GKEEN  SHALT  LIMESTONE. 


1  a.  Lychas,  and  1  b,  (undescribed.)  2  a.  Acidaspia.  2  b,  and  2  d. 
Shield  showing  the  spines.  2e.  Spine  of  the  buckler  enlarged. 
2/.  A  single  rib.  2  h.  Pygidium.  3  6.  4.  Eurypterus 

remipes  of  the  water  lime  group,  (young.) 


SILURIAN   SYSTEM.  123 

At  certain  places,  as  at  Becraft's  Mountain,  and  at  Schoharie,  a 
gray  limestone  succeeds  which  is  full  of  a  peculiar  species  of  pen- 
tamerus.  It  is  only  a  few  feet  thick.  According  to  the  present 
views  of  geologists,  this  last  mass  is  the  last  also  of  the  Silurian 
System.  It  may,  therefore,  be  seen  that  the  upper  part  consists  of 
a  series  of  pure  and  impure  limestones.  It  will  be  evident,  too, 
that  the  threefold  division  of  this  system  is  convenient,  and  aids 
the  memory  of  the  student. 

The  greenish  shaly  limestone  of  the  Helderberg  range  of  New 
York  is  probably  one  of  the  richest  rocks  in  fossils  of  the  Upper 
Silurian  System :  and  yet  this  rock  seems  to  be  quite  limited  in 
extent.  It  ranges  west  to  Cooperstown,  becoming  gradually  thinner ; 
it  however  carries  its  fossils  to  its  western  limit.  It  is  well  devel- 
oped in  the  Becraft  Mountain,  three  miles  east  of  Hudson  and  west 
of  Catskill,  N.  Y. 

The  bed  containing  the  Lychas  is  quite  limited;  the  species 
itself  is  closely  allied  to  the  Lychas  boltoni  of  the  Niagara  group. 
The  Acidaspis  is  also  quite  rare,  and  limited  to  a  thin  stratum  of 
rock  in  the  green  shales  of  the  Upper  Silurian.  The  spines  of  this 
genus  furnish  a  clue  to  its  recognition. 

The  Eurypterus  remipes  is  the  characteristic  crustacean  of  the 
water  lime.  It  is  furnished  with  eight  tentacular  organs,  four  being 
placed  on  each  side  of  the  head.  Its  organs  of  locomotion  were 
similar  to  oars,  rather  than  feet.  The  tail  is  attenuate  and  sharp- 
pointed. 

Under  the  name  and  form  of  Cliff  limestone,  which  is  both  sili- 
cious  and  inagnesian,  this  group  is  widely  extended  in  Indiana, 
Ohio,  Illinois,  and  Wisconsin;  and  is  7  to  800  feet  thick.  This  lime- 
stone supports  a  coralline  and  shelly  limestone  which  is  represented 
in  New  York  by  the  Onondaga  and  corniferous  limestones  of  the 
Devonian  system.  It  will,  therefore,  be  observed  that  several  rocks 
which  are  important  eastward  are  absent  in  the  west:  viz.,  the 
whole  of  the  Onondaga  salt  group,  the  water  limes,  Pentamerus 
limestone,  Delthyris  or  green  shaly  limestone,  Encrinal  limestone, 
and  Upper  Pentamerus  limestone.  The  student  will  understand 
from  the  foregoing  facts  that  the  Silurian  is  more  complete  in  New 
York  than  in  the  Western  States.  The  lower  mass  of  the  Cliff 
limestone  represents  the  Upper  Silurian,  and  yet  there  is  a  mixture 
of  Upper  and  Lower  Silurian  fossils,  as  the  Illsenus  crassicauda, 
Leptaena  alternata,  and  Phacops  caudatus. 


124 


MANUAL   OF   GEOLOGY. 


Table  showing  the  equivalency  of  the  New  York  members  of  the   Upper  Silurian 
with  those  at  a  distance. 


New  York. 
Onondaga  salt  group. 
Niagara  limestone. 
Coralline  limestone. 
Niagara  shale. 


Clinton  group. 


Western  States. 
Inferior  part  of  the  Cliff 
limestone  of  the  Ohio 
geologists    equivalent 
to  Upper  Silurian. 

Niagara     and'      Clinton  1 
groups    in   part,    con- 
taining     Pentamerus 
oblongus      and    Pha- 
cops  caudatus. 


England. 

Wenlock  limestone  and 
shales  and  Gothland. 


Stage  above  the  Cara- 
doc  sandstone. 


In  England  the  stage  represented  here  by  the  Clinton  group 
being  intermediate  between  the  Wenlock  and  Caradoc,  is  not  repre- 
sented there  by  any  yet  described  series ;  unless  by  Sedgwick,  who 
places  the  Mayhill  sandstone  and  Woolhope  limestone  in  a  position 
parallel  with  our  Clinton  group. 

The  Silurian  System  occupies  large  areas  in  the  northern,  western, 
and  southern  parts  of  the  United  States.  The  Lower  Silurian 
skirts  the  eastern  shore  of  Lake  Champlain,  and  exists  in  detached 
and  isolated  outliers  in  the  Hudson  River  Valley;  and  small 
patches  of  the  calciferous  sandstone  occur  as  far  east  as  Hoosic, 
Rensselaer  Co.,  N.  Y.  West  of  Champlain  it  extends  west  as  far 
as  the  parallel  of  longitude  of  97°,  and  as  far  south  as  Tuscaloosa 
in  Alabama.  Its  westward  and  southward  extent  therefore  is  about 
1500  miles.  At  these  extreme  southern  and  western  limits  the 
system  disappears  under  the  cretaceous  and  tertiary  rocks.  On  the 
north-western,  eastern,  and  south-eastern  borders  it  rests  unconform- 
ably  upon  the  Taconic  System. 


Fig.  112. 


Eyes  of  Trilobites,  showing  that  the  eyes  of  insects  of  the  present  day  are  constructed 
on  the  same  plan.    3.  Enlarged  lens. 


CHAPTER  XIII. 

DEVONIAN    SYSTEM. 

138.  THIS  system,  though  much  thicker  than  the  Silurian,  is  geo- 
graphically less  extended  in  this  country.  Like  the  Silurian,  it  is  one 
of  the  general  systems,  and  is  found,  it  is  believed,  in  all  the  great 
natural  divisions  of  the  earth's  surface. 

All  such  systems  indicate  certain  uniformities  in  the  operations 
of  nature,  as  well  as  simultaneous  movements  which  produced  ana- 
logous results  in  the1  same  epochs  in  the  history  of  the  earth.  In 
no  epoch,  however,  do  we  find  perfect  uniformity  in  the  quantity 
of  sediment  by  which  the  length  of  this  epoch  is  measured.  Re- 
markable differences  are  found  when  the  eastern  and  western  series 
constituting  this  system  are  examined.  Certain  subordinate  groups 
of  the  system  are  wanting,  and  in  others  the  system  does  not  exist 
at  all,  and  the  Carboniferous,  the  next  system  above,  lies  directly 
upon  one  of  the  members  of  the  Silurian.  Thus,  in  Kentucky 
one  member  of  the  Devonian  only  exists :  the  Genesee  slate  is  the 
only  rock  separating  the  Carboniferous  from  the  Silurian. 

In  Ohio  the  members  of  the  Devonian,  which  intervene  between 
the  Carboniferous  and  the  Silurian,  are  parts  of  the  Chemung 
group.  They  are  called  Olive  sandstones,  the  Genesee  slate,  Niagara 
group  or  part  of  the  Cliff  limestone. 

In  New  York  this  system  is  very  thick,  and  is  divisible  into 
many  groups;  but  westward  and  south-westward  it  constantly 
diminishes  in  thickness,  and  ultimately  disappears. 

In  England  and  Scotland  the  Devonian  holds  an  important  place. 
It  was  the  field  of  Hugh  Miller's  most  valuable  and  popular  labors. 
In  England  the  thickness  of  the  Devonian  is  eight  thousand  feet. 

Mr.  Lyell  states  that  on  the  coast  of  Rosshire  the  old  red  sand- 
stone forms  isolated  hills  resting  on  gneiss ;  the  strata  are  horizon- 
tal, and  only  three  thousand  feet  thick  in  consequence  of  denudation. 
In  this  region  it  is  evident  from  the  diminished  thickness  and  the 
11  *  (125) 


126  MANUAL   OP   GEOLOGY. 

insulation  of  the  hills,  that  forces  or  agents  have  worn  off,  and  cut 
down  these  strata  to  the  very  base  on  which  they  rest. 

But  the  most  interesting  fact  to  us  is  the  co-ordination  of  these 
distant  beds  with  our  own,  being  shown  by  the  similarity  of  fossils, 
or  the  close  affinity  of  fossils  which  identifies  this  distant  formation 
with  our  own.  Thus  the  remarkable  fish,  the  Holoptichius  nobi- 
lissimus,  is  common  to  both  countries  ;  the  asterolepis,  upon  which 
Hugh  Miller  bases  his  celebrated  argument  against  the  transmuta- 
tion theory,  is  also  common  to  both  countries. 

This  system  in  New  York  is  composed  of  the  following  rocks  and 
groups  of  rocks.  Oriskany  sandstone,  two  to  three  feet  thick,  but 
between  600  and  700  feet  in  Pennsylvania ;  Cauda  galli  grit  and 
Schoharie  grit,  seven  to  ten  feet  thick  ;  Onondaga  limestone  and 
corniferous limestone,  120  feet  thick;  they  really  form  but  one 
rock.  Marcellus  shale,  Hamilton  group,  Tully  limestone,  only  14 
feet  thick ;  Genessee  slate,  Chemung  group,  and  Cattskill  group. 
According  to  M.  De  Yerneuil,  the  lowest  rock  of  this  system  in 
New  York  is  the  Oriskany  sandstone.  If  we  take  the  Helderberg 
and  Cattskill  Mountain  group  as  the  type  of  the  system,  we  shall 
find  two  zones  of  shales  and  sandy  beds;  one  below  and  one 
above,  with  a  heavy  limestone  formation  between.  The  sand- 
stones and  sandy  beds  embrace  the  Oriskany  sandstone,  the  cauda 
galli  grit,  a  dark  drab-colored  silicious  shale,  above  which  there  is 
another  grit  only  seven  or  eight  feet  thick,  called  the  Schoharie 
grit ;  it  is  important  only  as  the  repository  of  many  fossils.  Upon 
these  repose  the  Onondaga  and  corniferous  limestones. 
.  The  latter  passes  into  shales,  which  are  soft,  dark-colored  or 
black,  and  in  some  parts  quite  calcareous.  They  contain  many 
peculiar  fossils,  and  they  have  become  generally  known  as  Marcellus 
shales.  The  Hamilton  group,  which  succeeds,  consists  of  shales 
and  silicious  beds  and  sandstones,  which  are  generally  thin-bedded 
and  dark-colored,  but  weather  to  a  brown.  Among  the  shales  there 
are  impure  calcareous  bands,  and  calcareous  matter  is  disseminated 
to  a  small  extent  through  different  bands  of  the  formation :  these  are 
the  best  repositories  for  fossils. 

The  Tully  limestone  succeeds  the  Hamilton  group;,  it  is  only  14 
feet  thick.  Upon  this  limestone  the  Genesee  slate  reposes ;  it  is 
thin-bedded,  black,  and  calcareous. 


DEVONIAN   SYSTEM. 


127 


Fig.  113. 
RHYNCONELLA  BARRANDI. 


1.  Side  view,  showing  its  ridges.    2.  Back  view.-It  is  believed  to  be  confined  to  the  Oriskany 
sandstone— the  lowest  member  of  the  Devonian  System. 

The  RhynconellaBarrandi  is  rather  common  at  Cumberland,  Md. 
It  is  one  of  the  largest  of  this  genus. 


MANUAL   OF   GEOLOGY. 


Fig.  114. 
SPIRIFER  ARENOSUS. 


1.  Spirifer  arenosus.    2.  Rensselaeria  ovoides.    3.  Etonia  peculiaris. 

The  Spirifer  arenosus  is  the  most  common  fossil  of  the  Oriskany 
sandstone.     It  often  occurs  in  casts.     See  111. — 5. 


DEVONIAN   SYSTEM. 


129 


Fig.  115. 


4.  Orthis  unguiformis.    5.  Cast  of  the  Spirifer  arenosm. 

The  Oriskany  sandstone,  though  thin  in  New  York,  contains  pro- 
bably all  the  fossils  which  strictly  belong  to  the  rock.  It  is  often 
a  mass  of  shells  or  the  cast  of  shells. 


130 


MANUAL   OF   GEOLOGY. 
Fig.  116. 


u 


P.  Sagittatus.    Enlarged. 
1, 1  a,  1 1>.  I  e.  Atrypa  impressa.    2.  Pentamerus  aratus.   2  a.  Side  view.    3.  Plearor)  r.cw 

The  mass  to  which  the  foregoing  fossils  belong  is  crowded  with 
them,  but  they  are  frequently  in  the  condition  of  casts. 


DEVONIAN    SYSTEM.  131 

The  Portage  and  Chemung  groups  succeed.  They  are  partly 
shales  passing  into  flagging-stone  and  rarely  into  thick-bedded  sand- 
stone. They  are  followed  by  the  Cattskill  group,  which  consists  of 
dark-colored  shales  which  frequently  alternate  with  red  shales  and 
sandstones.  It  has  been  regarded  as  the  equivalent  of  the  old  red 
sandstone  of  England  and  Scotland.  It  forms  the  greater  portion 
of  the  Cattskill  Mountains.  Conglomerates  occur  at  the  top  of  the 
Cattskill  rocks  belonging  probably  to  the  carboniferous  system. 

The  Devonian  System  does  not  exist  east  of  the  Hudson  River. 
West  of  the  Mississippi  the  Devonian  is  represented  by  either  the 
Portage  or  part  of  the  Chemung  group. 

The  fossils  of  the  Devonian  are  exceedingly  numerous,  and  differ 
remarkably  from  those  in  the  Silurian.  Its  most  interesting  fossils 
are  fish,  among  which  the  ganoids  are  conspicuous.  In  this  system 
reptiles  begin  their  career,  but  they  are  feebly  represented,  and 
only  foreshadow  the  future  of  this  important  class.  In  Europe  only 
two  reptiles  have  as  yet  been  discovered ;  the  Telerpeton  of  Mantell, 
and  the  Staganolepis ;  the  former  is  supposed  to  belong  to  the 
Batrachian  family ;  the  latter  has  a  close  resemblance  to  the  Teleo- 
saurus.  Plants  which  bear  a  resemblance  to  coal  plants,  and  are 
undoubtedly  of  terrestrial  origin,  begin  to  appear  in  the  upper  part 
of  the  system.  Corals  and  mollusca  abound  throughout. 

The  foregoing  groups  collectively  compose  the  Devonian  System. 
The  rocks  from  the  Genesee  slate  to  the  conglomerate  at  the  top 
of  the  Cattskill,  constitute  really  but  one  series,  though  for  con- 
venience it  has  been  subdivided  into  groups.  The  deepest  part  of 
the  Devonian  sea  appears  to  have  been  in  the  region  of  the  Catts- 
kill series.  The  prolongation  of  the  Devonian  and  Silurian  east- 
ward is  quite  limited.  There  is  no  Devonian  on  the  east  side  of  the 
Hudson  River.  The  Upper  Silurian  is  prolonged  four  or  five  miles 
eastward  of  the  city  of  Hudson,  and  forms  the  upper  part  of  Be- 
craft's  Mountain,  where  it  suddenly  disappears  towards  the  east. 

139.  The  valuable  products  of  the  Silurian  and  Devonian  of  this 
section  are  limestones  for  marble  and  for  quicklime ;  the  flag-stones 
belong  exclusively  to  the  Devonian.  No  ores  or  coal  belong  to 
either  system  in  this  part  of  the  state.  There  are  no  limestones 
proper  above  the  Tully  limestone. 

The  Devonian  in  Ohio  is  much  thinner  than  in  New  York.  Its 
members  are  called,  1st.  Olive-colored  sandstone,  which  are  equi- 
valent to  the  Chemung  group  in  New  York ;  the  Marcellus  shales, 


132 


MANUAL   OF   GEOLOGY. 


100  feet  thick,  and  the  Cliff  limestone,  the  upper  part  of  which,  is 
equivalent  to  the  corniferous  limestone  which  reposes  directly  upon 
and  is  conformable  to  the  blue  limestone  in  part  of  the  west,  and 
which  is  the  equivalent  of  the  Lorraine  shales.  In  the  South-west, 
in  the  county  of  Wythe,  the  Devonian  is  not  recognisable,  the  car- 
boniferous resting  directly  upon  the  Upper  Silurian,  or  the  Clinton 
and  Niagara  groups :  this  is  the  case  in  certain  places,  and  if  the 
Devonian  exists  at  all,  it  is  in  exceedingly  thin  masses,  and  will  be 
found  the  equivalent  of  the  New  York  Chemung  group. 


Fig.  117. 

FOSSILS  OP  THE  MIDDLE  DEVONIAN  SYSTEM,  OR  HELDERBERG 
LIMESTONE. 

7 


1,  2, 3.  Orthis  subcarinata.    4.  Orthis  oblata.    4  o.   Orthis  perelegana.    5.  Spirlfcr.    6,  Chonatei 
iMunUphericus  of  the  Schoharie  grit.    7.  Strophomena. 


DEVONIAN   SYSTEM. 


133 


Fig.  118. 


1.  Dalmania  selennrus.    2.  Cyrtoceras  undnlatus.    3.  Chonctes  lineata.    4.  Orthis  lenticular!* 
&  Atrypa  reticularis.    6.  Transverse  section  of  an  Ichthyodolerite. 

12 


134 


MANUAL   OF   GEOLOGY. 


Fig.  119. 


1.  Rensselaeria  (Meganteris)  elongata  (Hall).    2.  Atrypa  reticularis.    3.  Spirifor  undulatua. 


DEVONIAN    SYSTEM. 


135 


Fig.  120. 


1.  Cyrtoceras.    Back  view,  showing  the  undulating 
,  septse. 


2.  Ichthyodolerite  of  the  Onondaga  Limestone. 


136 


MANUAL   OF   GEOLOGY. 
Fig.  121. 


1.  2,  3,  4,  5.  Strophomena  Patersoni.  2.  Hinge  view 
and  muscular  impression.  3.  Edge  view.  6.  Stropho- 
mena inoquistriata.  7.  Strophomena  crenistriata. 


DEVONIAN   SYSTEM. 


MAKCELLUS  SHALES. 


Fig.  122. 


Fig.  123. 


1,  2.  Goniatites.    3.  Orthis  limitaris.  4 
Cypricardia  marcellanus. 


Bellerophon  patulus.  2.  Microdon  bellastriatM. 


12* 


138 


MANUAL   OF   GEOLOGY. 


Fig.  124. 
HAMILTON  GROUP. 


2.  Atrypa  gpinosa.    3.  Nucleospira  concinna.    4.  Strophomena  inequistriata  Con.    5.  Spirifer  zig- 
zag (Hall).    6.  Phacops  bufo.    6.  Dalmania  callitcles.    8.  Loxonema  nexilis. 

Fig.  125. 


1.  Fleurotomaria  lineata.  2,  3,  3.  Spirifer  mncronatns.    4.  Atrypa  priaca. 


DEVONIAN   SYSTEM. 


139 


Fig.  126. 


1  Orfchoceras  constrictura.    2.  Cypricardites  reeurva.    3.  Avicula  flabella.    4.  Discina  grandia. 


140 


MANUAL  OP   GEOLOGY. 


Fig.  127. 


2.  Spirifer  medialis.    3.  Spirifer  an 
.    4.  Cyrtia  Hamiltoniensis. 


Fig.  128. 


1,  2,  3,  4, 5.  Orthis  Vanuxemi.    1  e.  Hinge  view.    1  4. 
View  of  the  Ventral  Valve,    a,  6,  c.  Orthis  umbonatut. 


DEVONIAN   SYSTEM. 


141 


Fig.  129. 


2«,26.Tropidolepu8carmato8.  1,  2.  Strophomena  demissa.  1  a.  Muscular  impression.  2  a.  Young. 


142 


MANUAL   OP   GEOLOGY. 


Fig.  130. 


DEVONIAN    SYSTEM. 


143 


Fig.  131. 


Bpirifer  Maroyi.   Sa,  4a.  Hinge  view. 


144 


MANUAL   OF   GEOLOGY. 
Fig.  132. 


MO.  Cypricardites  (Gramysia)  Hamiltoniensis.    2.  Orthonota undulata. 

Cypricardites,  or  Gramysia  of  De  Vernueil,  is  one  of  the  cha- 
racteristic fossils  of  the  shales  and  sandstones  of  this  group.  The 
Orthonota  is  by  no  means  an  uncommon  fossil  in  the  same  series. 

The  Helderberg  Mountains,  Albany,  Co.,  N.  Y.,  and  the  ranges 
of  mountains  in  Schoharie  County,  are  also  depositories  for  the 
fossils  of  this  group. 


DEVONIAN    SYSTEM. 

Fig.  133. 
CORALS  OF  THE  DEVONIAN  SYSTEM. 


145 


1.  Heliophyllum  Halli.    2.  Eridophyllum  simconensis.    3.  Favosites  gothlandica.    4.  Syringopon. 
elegans.    5.  Aulopora  cornutum.    6.  Phillipsastrea  yerncnili.    7.  Zaphrentia  prolifera. 

13 


146 


MANUAL   OF    GEOLOGY. 
Fig.  134. 


nom«]nm.t".F  Dokavi.     Side. 


DEVONIAN    SYSTEM. 
Fig.  135. 


147 


Homalonottis  Dokayi.    Back  view. 


148 


MANUAL   OF   GEOLOGY. 


GENBSEE  SLATE. 
Fig.  136. 


2,  2.  Avicula  fragilis.    3.  Chonetes  setigera.    4.  Tentaculites  fissurella. 


i 


Fig.  137. 


Diacina  lodensis.    2.  Rhynconella  qoadrieoetata.    3.  Lingula  spatulata.    4.  Lingula  concentric*. 


The  Genesee  slate  is  a  black  fissile  rock,  and  rather  poor  in  fos- 
sils. The  fossils,  too,  are  small  and  obscure  in  the  state  of  New 
York. 


DEVONIAN    SYSTEM. 


149 


Fig.  138. 
CHEMUNG  GROUP. 


1,  2,  2  a.  Bellerophon  cyclopetrus.    1. 
View  of  the  top.    2  a.  Side  view. 


2.  Phaoops  nupera  of  the  Chemung  Group. 


13* 


150 


MANUAL   OF   GEOLOGY 


Fig.  139. 
CHEMUNQ  GROUP. 


«,  2,  3.  Produotus  hirautus.    4.  Productus  rarispinis.    5,  5,  6.  Produotua  Bojdii.    7.  Young  o< 
ftirstitus. 


DEVONIAN  SYSTEM. 

Fig.  HO. 
CATSKILL  GROUP,  OR  OLD  RED  SANDSTONE. 


151 


2.  Jaw  of  Holoptichius  Taylori 


Terabratula  lepida. 


152 


MANUAL   OF   GEOLOGY. 


Fig.  141. 


Lepidodendron  ?    Devonian  Plant. 


CHAPTER  XIV. 

CARBONIFEROUS  SYSTEM — AN  IMPORTANT  EPOCH A  STAND- 
POINT FOR  RECKONING  GEOLOGIC  TIME,  VEGETATION,  COAL, 
AND  PROSPECTIVE  MATERIAL  DESIGNED  FOR  THE  USE  OF 
MAN — FORMATION  ILLUSTRATED — VEGETABLE  FOSSILS DIVI- 
SION OF  THE  SYSTEM  INTO  LOWER  CARBONIFEROUS,  AND  THE 
COAL  MEASURES,  ETC. — RECAPITULATION. 

140.  THIS  system  fills  the  most  important  epoch  in  the  earth's 
history.     Unlike  the  Devonian  and  Silurian,  it  abounds  in  useful 
products,  and  these   products,  taken    collectively,  have  been  the 
most  direct  and  efficient  agents  in  promoting  that  high  degree  of 
civilization  which  now  prevails.     Of  these  valuable  products,  coal 
is  the  most  essential  material,  and  from  its  abundance  in  this  sys- 
tem it  has  derived  its  distinctive  name,  the  Carboniferous  System. 

To  the  geologist  it  is  often  a  point  of  departure  for  his  reckoning 
of  geologic  time,  or  it  may  be  employed  for  determining  his  true 
position  in  the  geologic  scale,  as  it  occupies  a  mid  position ;  and 
hence  the  past  and  future  are  necessarily  in  certain  determinable 
relations  which  may  be  viewed  with  great  advantages  from  this 
stand-point. 

Of  all  the  systems,  too,  it  is  more  constant  and  uniform  in  its 
characteristics,  when  continents  or  large  areas  are  compared,  than 
those  which  succeed  it.  This  statement  applies  both  to  its  fossil 
remains  and  its  mineral  constitution. 

141.  It  was  in  this  epoch  that  the  earth  began  to  wear  a  fairer 
and  more  promising  aspect.    It  was  clothed  with  a  vegetation  which 
would  bp  prized  by  civilized  man.    It  was  a  period  when  forests  of 
coniferous  trees  adorned  the  land ;  and  if  compared  with  the  Devo- 
nian, it  would  present  a  striking  contrast,  as  the  latter  has  pre- 
served no  trees  or  forests,  and  hence  it  is  probable  would  appear  as 
an  arid  or  barren  waste.     Previous  to  this  time  we  have  only  feeble 
indications  that  the  earth  was  watered,  as  it  is  now,  by  showers  of 
rain. 

(153) 


154  MANUAL   OF   GEOLOGY. 

In  the  carboniferous  series,  however,  there  were  soils  which  bore 
land  plants,  and  trees  of  a  large  growth ;  as  we  now  find  their 
remains  in  an  erect  position  with  their  roots  still  fixed  in  the  earth 
in  which  they  grew.  So  also  the  sandstones  and  shales  contain 
prostrate  trunks,  denuded  of  limbs  and  bark,  which  must  have 
drifted  down  rivers  and  finally  into  the  ocean,  where,  becoming 
water-logged,  they  sank,  and  were  buried  under  mud  and  sand. 

The  vegetable  kingdom,  then,  as  it  is  represented  in  these  relics, 
furnishes  unmistakable  evidence  of  progress.  Besides,  we  look  back 
to  this  epoch  with  great  interest  for  its  prospective  products,  its 
coal  especially,  which  we  believe  we  are  warranted  in  regarding  as 
a  special  provision  for  man.  We  can  view  in  no  other  light  these 
great  deposits  of  fuel,  which  required  ages  for  its  growth  and  sub- 
sequent consolidation  to  fit  it  perfectly  for  the  parlor,  the  workshop, 
and  steam-engine. 

142.  It  is  proved  by  direct  observation,  that  coal  is  of  vegetable 
origin.  By  the  aid  of  the  microscope,  it  is  found  composed  of  the 
vegetable  tissues ;  almost  every  particle  has  preserved  in  its  sub- 
stance ducts  or  vessels,  organs  of  growth  which  are  peculiar  to  the 
vegetable  kingdom ;  hence,  although  it  is  enclosed  in  beds  of  rock, 
it  has  an  origin  out  of  the  pale  of  the  mineral  kingdom. 

To  illustrate  the  circumstances  and  the  succession  of  events 
which  were  connected  with  each  other  in  the  production  of  coal  and 
the  formation  of  the  accompanying  beds,  we  may  refer  to  peat,  a 
substance  which  we  know  has  a  vegetable  origin.  In  the  first 
place,  peat  is  formed  only  in  cool  wet  places.  If  the  temperature 
is  much  above  75°  or  80°,  the  vegetable  matter  is  consumed ;  for 
example,  in  the  eastern  counties  of  North  Carolina  peat  is  formed, 
while  in  the  middle  counties,  though  the  surface  is  protected  by 
forests,  it  is  not  found,  neither  is  there  a  trace  of  bin  1:  vegetable 
mould.  Though  there  is  an  annual  addition  of  vegetabt'-  substance 
to  the  surface ;  it  is  all  consumed. 

But  the  low  grounds  of  the  eastern  counties  being  wet  and 
swampy,  the  temperature  never  reaches  that  point  at  which  a  slow 
combustion  takes  place,  as  is  the  case  in  the  middle  counties.  So 
also  we  infer  that  coal  plants  grew  only  in  grounds  which  were  wet 
and  cool,  though  the  temperature  of  the  uplands  may  have  been 
comparatively  high  as  at  the  present  time.  It  is  agreeable  then  with 
what  we  know  of  the  conditions  required  to  preserve  vegetable  matter, 


CARBONIFEROUS   SYSTEM. 


155 


and  convert  it  into  coal,  that  a  low  temperature  must  have  prevailed 
over  those  areas. 

143.  Peat  occurs  only  in  single  beds;  but  in  the  coal  measures 
numerous  beds  of  coal  occur  one  above  the  other,  which  are  sepa- 
rated by  a  variety  of  mineral  products.  Here  then  the  similarity 
in  the  circumstances  attending  the  production  of  peat  and  coal 
ceases.  It  becomes  necessary  to  explain  how  several  beds  may  have 
been  formed  in  succession  and  over  the  same  area,  for  it  is  plain 
that  each  bed  was  formed  at  the  surface  and  bounded  by  the  air 
above,  and  by  the  wet  soil  below  '}  and  that  each  coal  area,  as  in  the 
case  of  peat,  must  have  been  covered  with  growing  vegetables  while 
the  surface  was  virtually  stationary. 

To  account  for  the  occurrence  of  successive  beds  of  coal,  it  is 
supposed  'that  after  a  stratum  of  vegetable  matter  had  been  accu- 
mulated, a  subsidence  took  place  by  which  the  surface  was  sub- 
merged beneath  the  water,  and  that  sand,  clay  and  pebbles,  materials 
derived  from  neighboring  hills,  or  from  distant  parts,  which  would 
be  brought  down  by  rivulets  and  streams,  would  in  time  form  a 
sufficient  accumulation  of  debris  to  fill  up  the  basin  or  estuary ;  thus 
forming  a  swamp  or  morass  upon  which  a  new  vegetation  would 
spring  up  and  furnish  new  matter  for.  another  bed  of  coal.  We 
may  consider  then  that  repeated  subsidences  must  have  taken  place 
after  intervals  of  rest,  and  it  was  during  those  intervals  of  rest 
that  beds  of  sandstone,  shale,  underclays,  &c.,  were  deposited. 

This  figure  includes 
the  following  beds  as 
occurring  in  the  Nova 
Scotia  coal  measures. 

1.  Shale  and  sandstone. 
2.  Slate  and  sandstone 
with  erect  calamites.  3. 
Gray  sandstone  7  feet. 

4.  Gray  shale  4  feet,  with 
an  erect  coniferous  tree. 

5.  Sandstone  4  feet.      6. 
Gray  slate  6  inches,  with 
erect  and  prostrate  trees, 
rootlets,    leaves,    and    a 
inodiola.     7.    Main    coal 
measures  3  feet  6  inches. 
8.  Underclay  with  roots. 


Fig.  142. 


156 


MANUAL   OF   GEOLOGY. 
Fig.  143. 


Calamites  with  Leaves  and  Roots. 

144.  But  there  were  many  stationary  periods  which  are  not 
indicated  by  a  coal  seam ;  for  at  unequal  intervals  areas  occur  which 
were  covered  with  a  close  vegetation  embracing  trees  of  a  large 
size.  The  proof  rests  on  the  facts  that  underclays,  soft  sandstones, 
and  shales  are  penetrated  by  roots,  and  frequently  upon  what  were 
once  their  upper  surfaces,  stumps  and  trunks  of  trees  are  still 
standing  in  situ,  fig.  142.  All  such  areas  mark  a  stationary  period. 
The  most  common  roots  are  those  of  the  Sigillaria  and  Lepido- 
dendra;  the  former  had  a  fluted  trunk,  the  latter  was  singularly 
marked  with  rhombic  scars  of  leaves.  The  roots  of  the  former, 
however,  are  known  as  stigmaria.  They  frequently  have  the  strong 
fibre§  of  the  main  stem  of  the  root  still  attached.  Another  vege- 
table which  seems  always  to  have  grown  in  company  with  the  pre- 
ceding is  the  Calamites,  fig.  143,  with  its  fluted  and  jointed  stems. 


CARBONIFEROUS    SYSTEM.  157 

These  formed  jungles  similar  to  the  cane  brakes  of  the  Southern 
States.  Fig.  143  shows  the  verticillate  leaves  which  issue  from 
the  joints.  The  stem  terminates  below  in  an  obtuse  point. 

145.  The    Carboniferous   System   is  divided  into  two  parts,  a 
lower  and  an  upper.     The  lower  is  composed  lithologically  of  the 
Carboniferous  limestone.     The  upper,  or  coal  measures  proper,  are 
made  up  of  micaceous  sandstones,  conglomerates,  underclays  with 
superincumbent  coal   seams,  brown,  gray,  and  bituminous  shales 
with  clay  ironstones.     The  former  belongs  to  a  deep  sea  deposit, 
and  is  filled  with  marine  molluscs,  crinoids,  and  vertebrates,  which 
are  mostly  fish.     It  is  not  always  present ;  it  is  absent  in  the  Penn- 
sylvania coal  fields,  but  present  in  those  of  the  Western  States.    The 
latter  belongs  to  a  shallow  sea  or  to  estuaries  formed  in  the  imme- 
diate vicinity  of  land.     Land   plants,  swamp  and  jungle  plants, 
with  fragments  of  coniferous  stems,  characterize  the  coal  measures. 
Their  organic  contents,  it  will  be  seen,  are  widely  different  from 
those  of  the  limestone  below ;  and  hence  the  propriety  of  the  sub- 
division we  have  stated.     The  limestone  is  usually  some  shade  of 
gray ;  it  is  frequently  a  pure  limestone  and  fit  for  quicklime :  in 
others  it  contains  chert  or  hornstone.     It  has  been  divided  in  the 
Western  States  into  the  St.  Louis  limestone,  the  upper,  the  Archi- 
medes, the  middle,  and  the  encrinal  limestone,  the  lower  member. 
It  is  believed  by  many  that  there  are  two  or  three  different  beds 
of  the  Archimedes  division,  each  of  which  has  its  peculiar  fene- 
stella  or  coral  (Archimedes),  by  which  they  may  be  distinguished 
from  each  other.     They  form,  however,  properly  but   one  rock. 
The  first  and  second  divisions  are  remarkable  for  their  numerous 
beautiful  quartz  geodes ;  the  third  for  its  encrinal  remains.     The 
maximum  thickness  of  this  formation   is  between  750  and  800 
feet. 

146.  The  fossils  of  this   limestone  are  extremely  numerous. 
The  piscean  vertebrates  differ  essentially  from  those  of  the  preced- 
ing systems.    Fig.  144  (11)  is  a  tooth  of  a  fish  from  the  Pittsburgh 
coal  formation,  the  Petalodus  Alleghaniensis  (Leidy). 

147.  The  coal  measures,  taken  as  a  whole,  show  that,  though 
composed  of  divers  materials,  they  are  connected  by  a  continuous 
series  of  events  of  similar  kinds;    and   also  show  that  they  are 
bound  together,  and  form  parts  of  only  one  period  or  system.    They 
were  ushered  in  by  a  deposit  of  coarse  pebbles,  which  constitute  a 
massive  bed,  which  has  been  called  the  Millstone  grit. 

14 


158 


MANUAL   OP   GEOLOGY. 
Fig.  144. 


1.  Producing  carbonari  us.    2.  Spirifer  Marionensis  (do.)    3.  Productus  .    4.  Productns 

aequicostati.s.    5.  Jlodiola.    C.   Chonetes  ornata  (Shumanl).    7.  Discina.    8.  Productus  flemingi. 
9.  Alloristna  Ilannibalensis  (do.)    10.  Orthis  swallovi.     11.  Petalodus  alleghaniensis. 


CARBONIFEROUS   SYSTEM. 
Fig.  145. 


159 


1.  Actinocrinus  chrystil.  2.  Cyphaspis  girardeauensis  four  times  enlarged).  3.  Fusilina  cylindrioa. 
4.  Pentremites  Sayi.  5.  Pentremites  Koninckana.  6.  Pentremites  pyriformis.  7  and  7  a.  Conularia 
rernuelii  (half  the  size).  7  a.  surface  enlarged.  8.  Archimedes  Wortheni. 


160  MANUAL   OF   GEOLOGY. 

The  system,  litholog'.cally  considered,  is  composed  of  grits  and 
shales,  coarse  and  fine-grained  sandstones,  black,  gray,  and  bitu- 
minous shales,  fire-clays,  with  their  superimposed  coal  seams  and 
beds  of  clay  and  ironstones,  forming  together  a  series  of  overlying 
deoosits,  and  of  which  many  of  the  members  are  often  repeated. 
These  repetitions  could  only  occur,  as  we  have  already  explained, 
by  successive  submergences.  Sometimes  these  areas  existed  as 
deep  seas,  or  as  shallow  estuaries,  which  might  be  converted  by  sedi- 
ment into  bays,  swamps,  and  jungles ;  sometimes  again  we  find  deep 
marine  products ;  then  those  of  a  shallow  brackish  water,  as  in  estu- 
aries, the  latter  of  which  would  rapidly  change  and  become  an  area  for 
the  growth  of  vegetables  which  in  turn  would  be  changed  into  coal. 

A  modification  of  this  view  with  respect  to  the  stationary  periods 
should  be  alluded  to  in  this  place.  Thus,  instead  of  maintaining  a 
period  of  absolute  rest  during  the  growth  of  coal  plants,  it  has 
been  supposed  that  there  was  a  slow  subsidence  which  kept  pace 
with  the  upward  growth  of  the  vegetables.  Still  it  is  evident  the 
time  came  when  a  more  complete  subsidence  occurred ;  so  complete 
as  to  submerge  most  perfectly  the  entire  plant  bed,  and  of  placing 
them  so  deep  in  water  that  the  whole  mass  was  killed,  and  at  the 
iarne  time  secured  their  burial  under  beds  of  sand  and  clay. 

148.  In  many  of  the  thick  carboniferous  systems  these  stationary 
periods  are  numerous.     In  Nova  Scotia,  where  it  is  no  less  than 
14,000  feet  thick,  there  are  more  than  one  hundred }  all  of  which 
are  indicated  by  roots  in  the  strata  and  upright  trunks  and  stems, 
many  of  which  were  no  doubt  vast  forest  areas,  parts  of  which  were 
too  dry  to  preserve  the  carbonaceous  matter  of  a  rank  vegetation. 
These  forest  areas  have  preserved  casts  of  trunks  varying  from  a 
few  inches  to  three  feet  in  diameter,  equalling  in  size  those  of  our 
present  forests.    The  annexed  figures  represent  the  ancient  fern-like 
plants  and  stems  of  the  Sigillaria. 

Fig.  147  (1).  Alethopteris  rugosa.  Fig.  150,  A  leaflet  enlarged. 
Fig.  148,  Pecopteris  Sheafferi.  Fig.  146,  Sigillaria  attenuata. 
Fig.  146,  Sigillaria  Yardleyi.  Fig.  147,  Odontopteris  alata.  Fig. 
149,  Sphenophyllum  erosum. 

149.  Debituminization  of  Coal. — In  the  early  periods  of  geology 
of  this  country  it  was  supposed  that  the  unbituminized  or  anthracite 
coals  were  older  than  the  bituminous.     It  is,  however,  now  known 
that  both  varieties  belong  to  the  same  epoch ;  the  former  to  rocks 
which  have  been  disturbed,  fractured,  and  broken  up,  and  which 


CARBONIFEROUS    SYSTEM. 

Fig.  146. 
FLORA  OF  THE  CARBONIFEROUS  SYSTEM. 


161 


Sigillaria  attenuata  (Leaqx.) 

14* 


162 


MANUAL  OF   GEOLOGY. 
Fig.  147. 


roptaris  rugosa  (Lesqx.) 


CARBONIFEROUS   SYSTEM. 

Fig.  148. 
FLORA  OF  THE  CARBONIFEROUS  SYSTEM. 


163 


Sternbergia,  Nova  Scotia,  Jogging  coal  field. 


Sphenopteris  ? 


Pecopteris  Sheafferi  (Lesqx.} 


164 


MANUAL  OP  GEOLOGY. 


Fig.  149. 


Sphenophyllum.         Sphenophyllum  erosum. 


Pecopteris  (Alethropteris)  lonchitica. 


Alethropteria. 


CARBONIFEROUS    SYSTEM. 
Fig.  150. 


165 


Sphenopteris  allied  to  the  microloba. 


Nenropteris  undescribed,  South-western 
Virginia. 


Asteropbyllites  equisetiformii 


Annularia  sphenopbylloide* 


6ph«novhyllum  •maiginatom. 


166  MANUAL   OF   GEOLOGY. 

have  probably  been  subjected  to  a  temperature  sufficient  to  dissipate 
tlieir  volatile  matter.  The  heat  required  for  this  need  not  exceed 
400°  Fahr.,  especially  if  accompanied  with  the  escape  of  steam :  a 
degree  of  heat  insufficient  to  produce  a  material  change  in  the  tex- 
tuie  of  the  rocks  themselves,  or  to  destroy  the  plants  imbedded 
therein.  Or  we  believe  it  is  more  agreeable  to  all  the  facts  now 
known  to  ascribe  the  cause  of  debituminization  to  heat  disengaged 
by  the  collision  of  the  masses  when  the  upheaval  of  the  coal 
measures  took  place.  The  excessive  displacement  of  these  rocks 
has  affected  every  layer  of  the  mass  concerned.  The  obliteration 
of  specific  characters  of  the  fronds  of  the  ferns  and  other  vegetable 
fossils  show  the  effects  of  upheaval,  and  the  sliding  of  the  masses 
upon  each  other;  a  movement  which  could  not  take  place  without  the 
development  of  heat.  If  heat  had  been  propagated  from  below, 
from  igneous  masses,  the  lower  rocks  must  have  suffered  a  complete 
fusion  before  heat  to  a  sufficient  amount  could  have  been  disengaged 
to  have  effected  the  debituminization  of  the  coal.  Rocks  are  bad 
conductors  of  heat ;  hence  the  necessity  for  its  generation  in  the 
midst  of  the  masses  themselves  rather  than  in  ascribing  its  origin 
to  distant  heated  bodies  beneath.  Of  course  we  except  those  cases 
where  trap  is  found  in  the  immediate  vicinity  of  beds  of  coal. 

In  market  coals  are  frequently  distinguished  from  each  other  by 
the  color  of  their  ash ;  thus  there  are  red  and  white  ash  coals ;  the 
former  usually  have  the  most  clinker,  and  injure  the  grate  more 
than  the  white  ash.  The  white  is  firmer  and  less  broken,  and  is 
regarded  as  the  most  valuable  of  the  two.  These  remarks  apply 
to  the  anthracites  of  Pennsylvania. 

150.  Distribution. — The  British  provinces,  Nova  Scotia,  New  Brunswick,  and 
Newfoundland,  have  large  areas  underlaid  by  the  Carboniferous  System.  In  the 
United  States  the  Alleghany  coal  field  stretches  through  Pennsylvania,  Maryland, 
Virginia,  Tennessee,  to  Alabama,  a  distance  of  nearly  900  miles,  and  occupies  in 
part  a  width  of  country  about  200  miles.  It  is  not  to  be  understood  that  this  is 
now  a  continuous  bed :  it  is  interrupted  and  broken  by  upheavals  of  the  strata 
at  a  period  intervening  between  the  close  of  the  Carboniferous  and  the  beginning 
of  the  Triassic.  The  beds  of  Pennsylvania,  however,  are  identical  with  many 
in  Ohio,  and  hence  were  no  doubt  continuous  deposits  over  wide  areas.  Illinois, 
Michigan,  Iowa,  Missouri,  and  Kansas  possess  large  and  important  bituminous 
coal  fields  which  are  only  slightly  disturbed,  while  the  anthracite  coal  fields  of 
Pennsylvania  are  greatly  disturbed  by  upheavals  being  uplifted  into  anticlinal 
and  synclinal  axes.  It  is  strictly  mountainous,  the  axis  of  crests  running  north 
65°  to  70°  east. 


CARBONIFEROUS   SYSTEM.  167 

151.  Recapitulation. — We  have  said  that  the  Carboniferous  epoch 
is  a  stand-point  from  which  we  may  survey  the  past  and  future.  Let 
us  pass  in  review  some  of  the  leading  events  and  changes  which 
had  already  transpired  in  the  earth's  history.  Physically  the  earth, 
since  sediments  began  to  collect,  had  undergone  great  changes. 
The  plains,  valleys,  and  lower  mountains  had  received  thousands 
of  feet  of  debris,  and  what  was  once  a  rough  pinnacled  surface  of 
pyro-crystalline  rocks  is  now  covered  with  sediments  evenly  spread 
out,  forming  the  foundation  of  plains  and  gently  sloping  hills,  suit- 
able for  the  plough  and  other  implements  of  husbandry. 

But  the  vegetable  kingdom  has  kept  pace  with  the  physical.  At 
first  the  sea  only  produced  plants,  all  of  which  belonged  to  the 
lower  organisms  of  the  kingdom;  now  forests  of  pines,  inter- 
mingling with  palm-like  sigillaria,  equalling  in  size  apd  height  the 
largest  of  our  trees,  cover  large  areas.  Among  these  dark  green 
forests  the  ferns  and  fern-like  plants,  the  lycopodiums,  plants  analo- 
gous to  our  ground  pines,  are  the  most  conspicuous.  Vegetation, 
to  say  the  least,  is  rank,  forming  impenetrable  jungles  and  thickets. 
We  know  not  whether  the  mountains  were  clothed  like  the  plains, 
but  we  find  trunks  of  trees,  stripped  of  their  foliage,  imbedded  in 
the  sandstones'  of  this  period,  which  must  have  floated  down  some 
rapid  river,  and  finally  with  its  still  and  gentle  currents  were 
borne  out  to  sea,  where,  water-logged,  they  sank  and  were  buried 
in  sand  or  mud. 

But  what  of  the  animal  kingdom  ?  here,  too,  we  witness  pro- 
gress }  the  sea,  however,  is  still  the  field  in  which  life  is  strong :  its 
fish  of  the  higher  grade  verge  upon  reptilian  forms;  their  teeth 
and  scales  belong  to  types  of  this  class.  They  form  as  yet  only 
two  ranks,  the  ganoids  and  placoids ;  but  they  have  reached  their 
maximum  of  power,  notwithstanding  they  came  in  late  in  the  Silu- 
rian epoch.  Hence  we  have  the  reign  of  fish  extending  only  over 
two  full  epochs.  No  mammal,  either  of  the  land  or  sea,  or  an  air- 
breathing  thing,  has  yet  appeared,  except  a  feeble  Saurian  Telerpe- 
ton,  and  the  more  powerful  Stagonolepsis,  closely  allied  to  the  Teleo- 
saur  of  the  Jurassic,  and  the  small  Archegosaur  of  the  Carboni- 
ferous  age.  But  they  scarcely  represent  power  or  rank,  and  they 
rather  foreshadow  the  advent  of  this  powerful  race  of  the  Jurassic 
era.  But  many  forms  have  disappeared,  or  are  about  to  disappear. 
The  Trilobites  no  longer  exist,  and  forms  more  like  the  present 
have  taken  their  place.  The  Orthoceratites,  which  are  Cephalopods, 


168  MANUAL   OF   GEOLOGY. 

and  were  the  tyrants  of  the  seas,  in  the  Lower  Silurian  stage,  have 
also  become  nearly  extinct,  and  will  soon  be  replaced  by  the 
Belemnite  of  the  middle  ages.  So  also  wide  gaps  have  been  made 
in  the  Brachiopodian  ranks,  especially  in  the  family  of  the  Spirifers. 
These  and  analogous  forms  are  about  to  be  replaced  by  the  Os- 
treas  and  Terebratulas,  many  species  of  which  have  continued 
to  the  present  epoch.  If  the  law  of  progress  is  well  established,  the 
death  law  is  equally  so ;  for  not  a  Silurian  species  lives  in  the  Car- 
boniferous seas ;  yet,  in  all  the  millions  which  have  perished,  not  a 
typical  form  has  been  lost,  but  new  patterns,  based  on  the  same 
types,  seem  to  have  sprung  out  of  the  old. 

152.  If  any  epoch  then  in  the  earth's  history  is  worthy  of  being 
distinguished  above  all  others,  it  is  the  Carboniferous.     This  view 
is  sustained  by  two  considerations ;  it  is  the  epoch  when  the  most 
valuable  of  all  materials,  COAL,  was  deposited,  and   it  furnishes 
during  its  existence  a  magnificent  exhibition  of  a  flora  unsurpassed 
in  splendor  and  beauty,  as  in  extent,  by  all  the  epochs  through 
which  the  earth  has  passed.     During  this  epoch  there  seems  to 
have  been  a  greater  uniformity  of  temperature  and  climate  than 
had  been  witnessed  in  any  former  one.     Of  this  we  may  be  assured 
by  the  greater  number  of  plants  which  belong  to  the  same  species 
in  distant  parts  of  the  world.     The  coal  plants,  for  example,  of 
Europe  do  not  differ  materially  from  our  own ;  many  are  identical 
species.     In  this  particular,  then,  we  have  that  kind  of  evidence 
which  naturalists  rely  upon  to  prove  similarity  of  conditions  of 
distant  and  remote  parts  of  the  world. 

But  the  importance  of  this  epoch,  in  consequence  of  the  inex- 
haustible masses  of  fuel  which  have  been  preserved  in  its  rocks, 
cannot  be  over  estimated. 

Civilization,  as  we  have  said,  is  due  in  a  great  measure  to  the 
events  of  this  remote  period. 

Before  the  highest  order  of  our  plants  was  created,  before  a 
warm-blooded  animal  came  into  existence,  before  there  existed  in 
creatures  a  single  amiable  instinct,  we  see  a  full  provision  in  the 
economy  of  nature  for  the  wants  of  a  future  age  which  no  event, 
foreshadowed,  except  it  may  have  been  in  the  immense  store  of 
fuel  which  belongs  to  this  special  epoch. 

153.  But  there   is   another  aspect  under  which  we   ought  to 
regard   the  Carboniferous   epoch,  if  we   would   fully  understand 
its  importance ;  it  is  its  length,  which,  if  measured  by  the  depth 


CARBONIFEROUS    SYSTEM.  169 

of  its  sediments,  holds  the  first  rank  in  point  of  duration.  There 
is  a  fitness  in  this  respect  which  adds  immensely  to  the  probability 
of  the  view  we  have  taken,  aside  from  the  thickness  of  the  sedi- 
ments of  this  epoch.  In  all  arrangements  which  bear  the  impress 
of  prospectiveness,  there  is  a  consistency  in  time  and  means,  to  the 
end  foreshadowed.  There  was  to  be  laid  up  in  store  for  future  ages 
a  stock  of  fuel  for  the  nations,  that  the  development  of  human 
power  and  greatness  should  not  lack  in  the  essential  material  neces- 
sary to  carry  out  in  full  the  design  of  their  creation.  Time,  then, 
was  necessary  in  these  arrangements,  and  coal  being  of  vegetable 
origin,  the  slow  growth  of  centuries  multiplied  by  centuries,  would 
be  only  adequate  to  the  production  of  matter  for  a  single  seam. 
But  many  seams  were  demanded,  and  hence  the  depth  of  the  strata 
and  the  prolongation  of  the  epoch. 

154.  The  Carboniferous  epoch  then  standing  out  in  bold  relief 
from  all  others  which  preceded  it,  and  from  those  which  succeed, 
has  become  like  a  beacon  from  which  the  geologist  surveys  those 
anterior  changes  which  ushered  it  in,  as  well  as  the  posterior  ones 
which  have  followed.  It  witnessed  the  introduction  of  thousands 
of  new  forms  belonging  to  the  vegetable  kingdom,  as  well  as  the 
introduction  of  new  classes  of  animals,  so  that  the  aspect  which  it 
presented  had  no  similarity  to  any  which  preceded. 

The  previous  faunas  and  floras  reach  the  commencement  of  this 
epoch,  but  do  not  enter  it;  and  its  own  fauna  and  flora  have  nearly 
disappeared  from  the  earth  at  its  close.  It  is,  therefore,  a  well 
defined  epoch,  having  a  beginning  and  ending,  and  we  may  say  a 
middle  term  also,  which  marks  its  most  distinguished  and  charac- 
teristic aspect.  It  is  not  then  a  sudden  introduction  of  an  epoch 
starting  into  life  in  its  full  development,  but,  like  all  others,  it 
begins  with  an  introduction  of  a  minor  importance  with  an  exhibi- 
tion of  a  few  new  classes  which  increase  gradually,  evolving  con- 
tinually new  and  striking  phases  as  time  rolls  on,  until  we  see,  after 
the  passage  of  ages,  the  full  development  of  the  characteristics 
which  mark  unmistakably  an  epoch  entirely  new  in  the  world's 
history. 

The  history  of  the  rise  and  fall  of  nations  presents  an  analogous 
aspect,  rising  to  their  zenith  and  importance  by  successive  steps, 
until  finally  the  acme  of  power  and  rule  is  attained,  when,  by  a 
series  of  declining  ones,  it  merges  itself  into  a  new  order  of  things 

15 


170 


MANUAL   OF   GEOLOGY. 


155.  Comparative  View  of  the  Devonian  and  Silurian  Systems,  Exhibiting  their 
Relations  to  the  Carboniferous  as  it  Exists  in  Several  States  of  the  Union ;  the 
New  York  Series  being  taken  as  the  Standard  of  Comparison. 

New  York.  Pennsylvania.    S.W.Virginia.      Ohio.          Missouri. 


31 

30 
29 
28 
27 
26 
26 
24 
23 

I" 
I21 
«20 

19 
18 

Coal  measures 

Mt.  Limest 

Conglomerate  ? 
Cattskill  group     . 

Portage  and  Chemung  group 
Gencsee  elate     

Tully  limestone 

Marcellus  shale            . 

Corniferous  limestone    .  .  . 
Onondaga  limestone    .... 
Schoharie  grit    

Cocktail  grit    .... 



Oriskany  sandstone  

' 

17 
16 
15 
14 
13 
12 
11 
10 
9 

i; 

S   a 

5 
4 
3 
2 
1 

Encrinal  limestone 

Mthyris  shaly  limestone   . 
Pentamerus  limestone    .  .  . 
Manlius  water  lime 



Niagara  group 

Oneida  conglomerate   .... 

Utica  slate 

Trenton  limestone     
Black  River  limestone    .  .  . 
Bird's  Eye  limestone    .... 
Chazy  limestone  .  . 

Calciferous  sandstone  .... 
Potsdam  sandstone  .... 

I 

CARBONIFEROUS    SYSTEM. 


171 


In  explanation  of  the  foregoing  table  it  may  be  observed  that 
the  coal  measures  of  Pennsylvania  rest  upon  the  Cattskill  group,  or 
upper  rocks  of  the  Devonian,  the  Carboniferous  limestones  being 
absent ;  while  in  South-Western  Virginia  they  rest  on  the  Upper 
Silurian.  In  Ohio  the  Cattskill  group  is  absent,  and  hence  the 
coal  measures  repose  on  other  members  of  the  Devonian.  In  Mis- 
souri, Kentucky,  Tennessee,  and  Alabama  the  Lower  Carboniferous 
limestone  is  present;  and  it  rests  on  the  rocks  equivalent  to  the 
Chemung  group  in  Missouri.  In  South-Western  Virginia  a  series 
of  salt-bearing  rocks,  with  gypsum,  belong  to  the  Carboniferous 
series.  The  dotted  lines  represent  the  absent  rocks. 


Fig.  151. 


BigUlwri*  bilobn.    (Sharp's  Mountain.) 


Fig.  152. 


Dromatherium  sylvestre. 


CHAPTER  XV. 

PERMIAN  SYSTEM — PHENOMENA  MARKING  THE  CLOSE  OF  THE 
PALAEOZOIC  DIVISION — AUTHOR  OF  THE  SYSTEM,  AND  DERIVA- 
TION OF  ITS  NAME — CHANGES  IN  THE  ORGANIC  REMAINS — 
PERMIAN  OF  THE  ATLANTIC  SLOPE — DEVELOPMENT  IN  NORTH 
CAROLINA — SYSTEM  DESCRIBED  UNDER  THE  NAME  CHATHAM 
SERIES,  FOSSILS,  ETC. 

156.  THE  Palaeozoic  series  closes  with  this  system.  Not  because 
there  is  anything  peculiar  in  the  lithological  character  of  its  rocks, 
but  because  it  was  during  the  deposition  of  the  strata  which  belong 
to  it  that  the  animals  and  plants  which  are  closely  related  to  those 
of  the  preceding  epochs  mostly  disappear;  while  in  the  system  which 
succeeds  it  all  the  Palseozoa  are  absent.  In  Europe,  in  1846—7,  about 
166  species  belonging  to  this  system  had  been  described,  of  which 
148  are  said  to  be  characteristic  of  it,  and  18  were  found  in  the 
subjacent  Palaeozoic  rocks.  Its  name  is  derived  from  the  ancient 
government  of  Perm,  Russia,  where  the  series  consists  of  sand- 
stones, limestones,  and  conglomerates,  &c.  Phillips  and  Murchison, 
in  England,  had  already  proposed  separating  the  magnesian  lime- 
stone series  and  a  portion  of  the  sandstones  of  the  superincumbent 
from  the  New  Red,  and  forming  therefrom  a  distinct  system.  The 
base  of  this  system  is  the  Rotheliegende  of  the  Germans.  It  rests 
unconformably  upon  the  Carboniferous.  Hence,  it  appears  that  in 
Europe,  after  the  close  of  the  latter  period,  and  after  a  state  of 
comparative  rest,  the  earth's  crust  was  once  more  broken  up  by 
igneous  forces,  the  Palaeozoic  rocks  were  tilted  up,  and  hence  all 
the  subsequent  rocks  were  deposited  on  their  upturned  edges. 

(172) 


PERMIAN    SYSTEM. 


173 


From  these  physical  movements  we  have  reason  to  expect  that 
changes  equally  great  in  the  organic  kingdoms  must  have  followed, 
for  it  seems  to  be  a  law  that  terrestrial  movements  have  resulted  in 
bringing  about  essential  changes  in  the  distribution  of  water  and 
other  physical  conditions  which  affect  unfavorably  life  in  the  aggre- 
gate ;  for  in  the  overlying  deposits  we  miss  the  forms  which  are 
Familiar  to  us,  and  find  them  replaced  by  new  ones,  which  are 
fitted  for  the  new  conditions  which  have  resulted  from  those 
changes.  But  species  die  out,  and  are  replaced  by  new  ones  during 
periods  of  quietude,  and  even  quite  a  number  may  survive  a  period 
of  disturbance,  and  pass  from  one  system  to  another. 

This  system,  in  Germany,  is  formed  essentially  of  three  mem- 
bers, the  Rothetodteliegende,  Zechstein,  and  Kupferschiefer,  and 
in  England  by  the  Lower  New  Red  Sandstone  and  Magnesian  Lime- 
stone. In  Russia  there  are  also  beds  of  limestone,  which  have  been 
identified  with  the  Zechstein  and  Magnesian  limestone,  and  which 
are  also  surmounted  by  marls,  spotted  sandstones,  and  conglome- 
rates. In  all  the  countries  of  Europe  the  foregoing  members  are 
quite  similar  lithologically  ;  besides,  they  are  connected  together  by 
a  similarity  of  fossils. 

157.  There  are  many  important  changes  in  the  fossils  of  this 
era  which  should  be  noticed.  Taken  as  classes  the  Brachiopods 
have  diminished  considerably  j  but  there  are  still  remaining  in  the 
Permian  30  species  at  least,  of  which  10  are  common  to  the  car- 
boniferous ;  that  is,  about  one-third  be- 
belong  to  the  latter.  The  most  common 
Brachiopod  is  the  Productus  horridus, 
fig.  153. 

The  Gasteropods  and  Cephalopods 
have  both  greatly  diminished  in  num- 
bers. Goniatites,  Nautili,  and  Ortho- 
ceratites  are  almost  all  unknown  in  the 
Permian. 

The  Crustaceans  are  represented  by  Productus  horridus. 

the  genus  Limulus.     The  fishes  are  peculiar  to  the  system. 

In  Russia  the  limestones,  in  England  the  Dolomitic  conglomerate, 
and  in  Germany  the  Kupferschiefer,  contain  bones  of  Thecodont 
Saurians. 

There  are  two  extensive  areas  over  which  the  Permian  is  proba- 

bly spread  in  the  United  States,  the  Atlantic  slope,  and  a  large 

15* 


MANUAL   OP   GEOLOGY. 


portion  of  the  Western  States  and  Territories.  I  he 
lithological  characters  are  quite  different  in  these 
two  sections  of  the  Union.  We  shall  select  only 
a  few  localities  for  the  illustration  of  this  series. 
Greenfield,  Mass.,  and  the  adjacent  country  in  the 
neighborhood  of  Turner's  Falls,  give  us  an  interest- 
ing series,  the  lower  part  of  which  we  place  in  the 
Permian. 

158.  The  Greenfield  Section  embraces  the  following  beds  :— 
Fig.  154,  a  coarse  red  conglomerate  :  6,  red  sandstone  with  a 
few  pebbles ;  c,  gray  brecciated  conglomerate  j  A,  trap.  This 
series,  from  a  to  A,  is  about  2200  feet.  The  trap  divides  the 
sandstone,  and  we  find  on  the  east  side  of  it  1,  red  shale  and 
red  sandstone,  which  are  impressed  with  the  earliest  foot- 
prints which  hitherto  have  been  regarded  as  the  prints  of 
birds'  feet.  2.  Brecciated  conglomerate.  3  and  4.  Red  sand- 
stone alternating  with  pebbly  beds.  5.  Shaly  sandstone  with 
footprints.  6.  Red  sandstone.  7.  A  dark-colored  shale  with 
footprints.  8  and  9.  Crushed  beds  consisting  of  fine-grained 
calcareous  sandstones.  10.  Gray  sandstone  and  dark-colored 
flags.  11.  Slates.  12.  Coarse  conglomerates.  13.  Dark- 
colored  flags  with  footprints,  at  a  place  known  as  the  Horso 
Race  on  the  Connecticut  River.  14  and  15.  Slates  alternating 
with  pebbly  beds.  They  form  the  upper  part  of  this  series. 
The  first  2200  feet  only  are  regarded  as  Permian.  The  casts 
of  vegetable  stems  agree  in  character  with  the  lowest  sand- 
stones in  North  Carolina. 

159.  The  following  section,  which  is  only  refer- 
red to,  is  similar  to  the  preceding  in  part.  It  illus- 
trates the  beds  which  we  have  called  the  Chatham 
series,  in  North  Carolina.  It  is  the  most  southerly 
series  upon  the  Atlantic  slope.  In  the  ascending 
order,  there  are  conglomerates  from  50  to  60  feet 
thick ;  red  and  brown  sandstones  and  marls,  which 
terminate  in  gray  sandstones,  which  sometimes  be- 
come reddish  after  long  exposure  to  the  air.  We 
regard  the  Lower  Red  sandstones  as  equivalent  to 
the  German  Rothetodteliegende.  Upon  this  sand- 
stone repose  the  bituminous  slates,  coal,  and  black- 
band,  succeeded  by  gray,  sandy  shales,  finely  rippled, 
and  marked  also  with  insect  trails,  followed  by 
repetitions  of  bituminous  shale,  coal,  black-band, 
and  fire-clay.  Then  follow  thin  beds  of  greenish. 


PERMIAN    SYSTEM.  175 

calcareous  shales,  containing  magnesia,  alternating,  repeatedly, 
with  bituminous  shales.  The  whole  thickness  of  these  shales  is 
at  least  600  feet.  Gray  sandstone  follows,  which  is  often  finely 
rippled ;  and  then,  beds  of  conglomerate,  alternating  with  bluish, 
non-bituminous  shale,  with  lignite,  and  stems  of  silicified  wood, 
together  with  greenish,  sandy,  and  gray  shales  and  sandstone, 
with  cycads,  gray  sandstone,  and  mottled  or  spotted  sandstones 
and  marl.  Near  the  top  of  the  series,  in  many  places,  there  is 
a  compact  gray  magnesian  limestone,  which  contains  a  few  fossils. 
The  Triassic  series  is,  probably,  unconformable  to  t"he  Chatham 
series.  The  upper  part  is  often  highly  charged  with  pebbles; 
and  on  the  Dan  river,  it  is  coarsely  brecciated.  These  conglo- 
merates are,  undoubtedly,  parallel  with  those  on  the  Connecticut 
river,  at,  or  near  the  Horse  Race. 

160.  Fossils  of  the  Lower  Red  Sandstone  Shales,  Black-band, 
&c.,  Fig.  155. — Chondrites  interruptus.  In  the  upper  part,  below 
the  bituminous  shales,  we  have  found  a  biconcave  vertebra,  and 
other  bones,  supposed  to  belong  to  a  Thecodont  Saurian.  (Fig.  160). 

Fossils  of  the  Bituminous  Shales,  Coal,  Black-band,  Ore,  &c. — 
The  most  interesting,  is  the  jaw  of  an  insectivorous  mammal,  fig.  152, 
twice  the  natural  size — the  Dromatherium  sylvestre.  It  is  the 
lower  jaw,  and  belonged  to  the  oldest  known  mammal.  The  next 
most  interesting  fossil,  is  the  Rutiodon  Carolinensis,  fig.  157;  a.  a 
premaxillary  bone ;  b.  nostrils.  The  premaxillary  is  subcylindrical, 
and  consists  of  one  solid  piece.  The  original  is  30  inches  in  length. 
The  teeth  of  this  Saurian  are  all  fluted  more  or  less  distinctly ;  in 
which  respect  it  differs  from  the  Clepsisaurus  of  Lea,  fig.  158. 
1,  2,  8,  4,  5,  6,  7,  8,  represent  the  teeth  of  the  Clepsisaurus.  7 
and  8,  are  transverse  sections. 

The  upper  jaw  of  the  Rutiodon  is  nearly  cylindrical,  as  it  is  pro- 
longed in  front  of  the  nostrils,  which  are  just  anterior  to  the  large 
eye-sockets,  and  descend  vertically,  like  the  blow-holes  of  a  ceta- 
cean. Notwithstanding  this  prolongation  of  the  snout,  and  its 
spoon-like  enlargement  at  its  end,  it  differs  materially  from  the 
Teleosaurus  of  the  Lias.  (Fig.  158  ;  11,  12,  different  forms  of  the 
teeth  of  the  Palaeosaurus.) 

The  Chatham  series,  and  indeed,  the  lower  beds  of  the  entire 
formation,  which  ocupy  the  Atlantic  slope,  rests  upon  either  the 
pyrocrystalline  rocks,  or  the  slates  of  the  Taconic  System.  In  North 
Carolina,  beds  of  porphyry  support  the  lower  red  sandstone,  and 


176  MANUAL   OF   GEOLOGY. 

hence  we  are  deprived  of  a  clue  to  the  age  of  the  series,  by  the 
absence  of  all  the  systems  between  the  Taconic  and  Carboniferous. 
In  the  Western  States  and  Territories,  however,  the  so-called  Per- 
mian, first  recognised,  we  believe,  by  Mr.  Meek,  succeeds  the 
Carboniferous,  with  which  it  is  also  conformable ;  and  many  Car- 
boniferous species  are  intermingled  with  those  fossils,  which  are 
supposed  to  be  Permian  species.  There  is,  therefore,  reason  for 
raising  the  question,  whether  the  upper  beds,  which  are  regarded 
as  Permian,  may  not  be  classed  with  the  Carboniferous. 

161.  Distribution. — Upon  the  Atlantic  slope,  especially  in  North 
Carolina,  the  evidence  of  the  Permian  age  rests  on  the  presence  of 
Thecodont  Saurians,  which  in  England  are  referred,  by  the  best 
geologists,  to  this  system.  In  North  Carolina,  this  view  is 
strengthened,  by  the  presence  of  the  Trias,  which  is  superimposed 
upon  the  beds  which  contain  the  Saurians  in  question.  There  would 
have  been  less  objection  to  this  view,  no  doubt,  had  the  Droma- 
therium  been  found  in  the  Trias,  or  in  the  rocks  of  the  Mesozoic  age. 
Assuming  the  observations  of  many  geologists  respecting  the  Per- 
mian elsewhere  in  this  country  as  correct,  it  is  evident  this  system 
occupies  a  wide  area  westward.  It  exists  in  Illinois,  Kansas, 
Nebraska,  at  the  Black  Hills,  Missouri,  and  New  Mexico.  "Its 
boundaries,  however,  are  undetermined. 


Labyrinthodont  of  the  Trias  restored,  with  its  foot-prints. 


PERMIAN     SYSTEM. 


177 


Fig.  155. 
PLANTS  OF  THE  CHATHAM  SERIES. 


Chondrites  interruptus. 


178 


MANUAL   OF   GEOLOGY. 


Fig.  156. 
PLANTS  OF  THE  CHATHAM  SERIES. 


Sphenopteris  Egyptiaca. 


o 


Saurian  Teeth  of  the  Bitumi- 
nous Slates  of  the  Chatham 
Series,  N.  C.  (Twice  natural 
si.e.) 


PERMIAN    SYSTEM. 
Fig.  157. 


179 


Eutiodon  Carolineasia.   a.  Premaxillary  bone.    6.  Nostril*. 


180 


MANUAL   OF   GEOLOGY, 
Fig.  153. 


i,  2,  3,  4,  5,  6,  7,  8.  Teeth  and  sections  of  the  teeth  of  the  Clepsisaurus  Pennsylvanicus.  9.  Pos- 
terior of  the  skull  of  the  Dictyocephalus  elegans,  Leidy.  a.  Oecipitals.  b.  Parietals.  c.  Frontals.  d. 
Post  Frontals.  t.  Post  orbitals.  /.  Squamous.  g.  Mastoids.  h.  Typanics.  t.  Zygomatics.  10.  Cra- 
nial Plate  of  tho  Dietyocephalus.  II  and  12.  Teeth  of  a  Palaeosaurus  ?  13.  Phalange  of  the  !•>••'  i  - 
Tooth  of  a  Pycuodont. 


PERMIAN    SYSTEM. 


181 


Fig.  159. 


1.  Dermal  Plate  of  a  Saurian.    (Natural  size.) 


Cranial  Plate  of  a  Saurian  (undescribed.) 


Cranial  and  dermal  plates  of  the  kind  represented  above  have 
been  found  only  in  the  upper  part  of  the  lower  sandstone. 


16 


182 


MANUAL   OP   GEOLOGY. 


Fig.  160. 
SAURIANS  OP  THE  CHATHAM  SERIEH. 


2.  Biconcave  Vertebra  of  the  Clepsisaurua. 


1.  Doable-headed  Kib  of  the  Rutiodon. 

The  strong  analogy  which  exists  between  the  Saurians  of  the 
Chatham  series  and  the  Bristol  conglomerate,  Eng.,  has  led  us  to 
place  the  series  in  the  Permian  System,  notwithstanding  the  ex- 
istence of  the  mammal  already  referred  to.  The  vertebrae  are  not 
only  biconcave,  but  in  other  important  respects  resemble  those  of 
the  Thecodonts  of  the  English  beds  which  are  regarded  as  Permian. 


PERMIAN    SYSTEM. 


183 


Fig.  161. 
FISH  REMAINS  OF  THE  CHATHAM  SERIES. 


Rabdiolepis  speciosus. 


Stile  of  the  fin  of  a  fish. 


184 


MANUAL   OP  GEOLOGY. 


Fig.  162. 
LABYEINTHODONT  OF  THE  CHATHAM  SERIES. 


Head  of  the  Dictyocephalus  elegans  (Leidy). 

This  skull  belonged  to  a  Labyrinthodont,  and  is  probably  allied 
to  the  Archegosaums.  The  cranium  is  partially  restored ;  the  pos- 
terior part  is  complete,  exhibiting  the  double  condyles  of  this  order 
of  Saurians.  Fig.  158—9.  The  plates  are  designated.  The 
restoration  was  made  by  Prof.  Leidy. 


CHAPTER  XVI. 

TRIASSIC    SYSTEM — DIVIDED    INTO    THREE    MEMBERS — BASE    OP 

THE     MESOZOIC     DIVISION MINERAL    CONTENTS — ITS     FAUNA 

AND   FLORA — IMPRINTS   OF   THE   FEET   OF   BIRDS   AND   BATRA- 
CHIANS. 

162.  THIS  series  is  composed  of  three  distinct  members :  the 
Bunter  sandstone,  the  inferior,  the  Muschelkalk,  the  middle,  and  the 
Keuper,  the  superior  member.     The  lower  and  upper  are  shoro 
deposits ;  the  middle,  a  deep  marine  deposit,  which  is,  no  doubt, 
partly  a  mechanical,  and  partly  a  chemical  formation.     It  is  fre- 
quently absent,  as  in  England  and  America.    It  is  rich  in  molluscs, 
and  hence  its  name. 

Although  this  system  is  the  base  of  the  Mesozoic  division,  it  is 
still  conformable  to  the  Permian,  presenting,  in  this  particular,  an 
anomaly,  when  the  relative  position  of  the  latter  is  considered ;  for 
this  system,  the  Permian,  is  discordant  to  the  Carboniferous,  upon 
which  it  rests.  It  seems,  therefore,  there  is  a  break  in  the  series 
at  the  wrong  place;  it  should  have  been  at  the  commencement  of 
the  Mesozoic  division,  the  base  of  the  Trias. 

The  progress  of  discovery  has  brought  to  our  knowledge  much 
that  tends  to  obliterate  the  strong  lines  of  demarkation  between  the 
Palaeozoic  and  Mesozoic  divisions.  Quite  a  number  of  Palaeo- 
zoic genera  pass  up,  and  are  associated  with  those  of  the  middle 
division.  Still,  there  are  grounds  for  regarding  the  Trias  as  indi- 
cative of  a  new  era,  by  the  introduction  of  a  new  class  of  vertebrates, 
the  birds ;  such  an  event  certainly  should  be  marked  in  our  sub- 
divisions of  the  strata. 

163.  This  system  contains  beds  of  rock-salt,  brine  springs,  and 
gypsum,  and  hence  has  been  called  the    Saliferous  System,  and 
hence,  too,  is  important  for  its  valuable  mineral  contents. 

But  its  fauna  and  flora  confer  a  special  interest  upon  the  system 
The  animals  are  peculiar;  the  Saurians,  for  example,  are  Labyrin- 
thodonts,  which   partake   strongly  of  the  Batrachian   type.     In 
16  *  (185) 


186  MANUAL   OF   GEOLOGY. 

Europe,  a  single  mammal  has  been  found,  the  Microlestes,  in  its 
upper  member  the  Keuper.  But  our  interest  in  the  series  is 
greatly  heightened  by  the  evidence  that  birds  appeared  upon  this 
planet,  for  the  first  time  during  this  epoch.  The  inference  to  this 
effect,  is  based  on  foot-prints  upon  the  strata,  which  possess 
all  the  characteristics  of  this  class  of  bipeds — a  foot-print,  pro- 
vided with  the  three  toes  in  front,  and  the  requisite  number  of 
joints  to  each  toe.  Some  years  ago,  the  enormous  size  of  the  foot- 
prints, created  some  doubt  of  their  having  been  made  by  birds ; 
but  discoveries  of  the  remains  of  birds  of  gigantic  stature,  in  New 
Zealand,  have  dispelled  those  doubts.  Fig.  163,  imprints  of  birds' 
feet,  in  the  shale  of  Turner's  Falls,  Mass.  In  similar  shales,  and 
near  the  same  horizon,  fish  remains  are  numerous.  Fig.  164  is 
the  Eurinotus  ceratocephalus  ;  it  is  an  unique  specimen,  exhibiting 
appendages  upon  the  front  part  of  the  head.  It  is  associated  with 
the  genus  Ischypterus,  which  occurs  at  Sunderland,  Mass.  At 
Boonton,  N.  Y.,  similar  beds  of  shale  contain  fish  remains,  of  the 
same  species  as  those  of  Turner's  Falls  and  Sunderland.  In  North 
Carolina,  fish  remains  of  the  same  family,  occur  in  the  upper  sand- 
stone. 

164.  The  lithological  characters  of  the  Trias  are  exceedingly  varied. 
Red  sandstones  and  shales,  often    mottled,  prevail,  but  gray  and 
red  conglomerates,  red  shales,  calcareous  shales,  of  a  reddish  tint, 
bituminous  shales,  of  a  black  color;  also,  black,  purple,  green,  and 
spotted  shales,  which  are  not  bituminous  or  commpn.     As  in  other 
systems,  its  base  is  a  conglomerate.     Near  Turner's  Falls,  in  the 
vicinity  of  Greenfield,  the  conglomerate  is  gray,  and  numerous  beds 
of  different  lithological  characters  succeed,  in  the  order  represented 
in  fig.  154.     This  section  was  referred  to  in  the  notice  of  the  Per- 
mian system,  but  is  more  particularly  described  in  this  place.     Thus, 
from  a  to  A,  conglomerates,  red    sandstone,  usually  coarse,  and 
often  pebbly,  embracing  a  thickness  of  over  2000  feet. 

165.  A.  Heavy  beds  of  greenstone  which  divide  the  formation  on  the  east  side  of 
the  greenstone.     1.  Red  shales.     2.  Conglomerate  traversed  by  a  trap  dyke.     3. 
Red  sandstone.     4.  Red  sandstone  alternating  with  pebbly  beds.     5.  Shaly  sand- 
stone with  footprints  of  birds.     6.  Red  sandstone.     7.  Thin  shaly  dark-colored 
beds  with  footprints.     8.  Broken  and  crashed  beds  of  fine-grained  calcareous 
sandstone.     9.   Fine-grained   calcareous   sandstone.     10.   Gray  sandstone  and 
dark-colored  flags.     11.  Slates.     12.  Coarse  conglomerate.     13.  Gray  and  dark- 
colored  flags  and  slate  with  footprints.   14.  Slates,  alternating  with  pebbly  beds— 


TRIASSIC   SYSTEM. 


187 


Fig.  163. 
IMPRINTS  OF  FEET. 


Imprints  of  the  Feet  of  Birds. 


Imprints  of  the 


188 


MANUAL   OP   GEOLOGY. 

Fig.  164. 
FISH  REMAINS. 


1.  Eurinotus  coratocephalus. 


TRIASSIC    SYSTEM.  189 

some  of  which  are  coarse.     This  series  embraces  a  thickness  of  not  less  than 
5000  feet. 

The  materials  composing  these  beds  are  derived  from  the  neighboring  talco- 
micaceous  slates  and  granites.  In  the  conglomerates  large  fragments  of  inica 
slate  are  common — exceeding  a  foot  in  diameter — they  are  both  angular  and 
rounded. 

We  may  recognise  two  movements  while  the  foregoing  sediments 
were  being  deposited ;  the  first,  immediately  preceding  the  deposit 
of  the  gray  conglomerate,  No.  1 ;  the  second,  towards  the  close  of 
the  period,  at  No.  12,  and  which  seems  to  have  been  frequently 
repeated  until  its  close. 

160.  The  Triassic  series  are  exposed  in  Wake  and  Orange  counties,  N.  C.  The 
railroad  leading  from  Raleigh  to  Hillsborough  passes  over  them  nearly  at  right 
angles  to  the  dip  of  their  beds.  At  Morrisville,  12  miles  from  Raleigh,  the  lower 
conglomerates  are  visible — and  in  proceeding  to  Durham  Station  the  dip  may  be 
seen  at  numerous  places,  inclining  at  about  an  angle  of  10°  to  the  north-west. 
This  being  the  regular  dip  of  the  series  here,  we  conclude  that  there  is  an  un- 
conformability  between  these  beds  and  those  which  belong  to  coal  measures  of 
Deep  river,  for  there  the  dip  is  south  and  south-west.  It  is  also  fully  ascertained 
that  the  latter  are  absent,  and  the  former  repose  on  the  older  slates. 

This  series  is  remarkably  well  developed  on  the  North  Pennsyl- 
vania Railroad,  beginning  near  Fort  Washington  Station,  Pa.  This 
road  crosses  the  entire  series.  At  Gwynedd  Station,  the  tunnel 
cuts  through  a  part  which  corresponds  with  the  Phoenixville 
Station.  Several  beds  of  black  and  green  slates  frequently  occur, 
as  partings  between  heavy  beds  of  a  tough,  brownish,  granular 
sandstone.  This  part  has  been  disturbed,  and  seams  of  calcspar 
are  common  in  the  tunnel,  in  which,  also,  may  be  seen  solid 
bitumen,  or  coal.  A  Posidonia  occurs  at  Gwynedd,  and  frequently, 
worm-tracks,  and  rarely  a  calamite.  After  passing  the  tunnel,  the 
rock  is  mostly  a  shaly  sandstone,  with  fucoids.  This  belt,  between 
Gwynedd  and  the  next  station  north,  corresponds  to  one  near 
Greenfield,  Mass. 

167.  The  most  interesting  relics  of  the  Trias,  as  already  stated,  are 
the  imprints  of  the  feet  of  birds,  inasmuch  as  they  furnish  indica- 
tions that  the  earliest  existence  of  this  class  of  animals  is  found  in 
this  formation.  The  imprints  already  referred  to  were  made  by  a 
biped.  The  substance  of  the  rock  was  soft  at  the  time  they  were 
made,  and  hence  there  is  a  want  of  sharpness  in  the  outline  of  the 
foot.  Birds  of  gigantic  size  strode  along  the  beaches  of  olden 
time,  if  the  imprints  of  their  feet  furnish  a  criterion  of  size  and 
weight.  For  example,  there  are  footmarks  in  the  Trias  of  Con- 


190 


MANUAL   OP   GEOLOGY. 


Fig.  165. 


Trails  of  Insects. 


necticut,  which  measure  seventeen  inches  from  the  heel  to  the 
point  of  the  middle  toe.  Others  are  small,  and  resemble  the  im- 
prints of  the  feet  of  small  shore-birds,  not  unlike  those  of  the  pre- 
sent day. 

But  imprints  of  various  kinds  are 
common  upon  the  fine  sandy  deposits ; 
even  insects  have  left  their  trails. 
Whoever  is  at  pains  to  observe  the 
surfaces  of  fine  plastic  clays  after  a 
shower  will  find  trails  of  larva,  and 
also  of  perfect  insects,  around  the 
parts  of  water  which  are  left  stand- 
ing by  roadsides  and  in  undisturbed 
fields.  Fig.  165  shows  the  trail  of 
what  appears  to  have  been  made  by 
larva  of  some  dipterous  insect,  pre- 
serving also  the  impression  of  rain- 
drops. (See  also  pi.  vi.  American  Geology,  figs.  105,  106,  107, 
108).  So  also  in  the  ancient  Trias,  at  Turner's  Falls,  furnish  trails 
of  insects,  of  which  fig.  109,  of  the  same  work,  is  an  example. 

168.  The  Mollusca  (Entomostraceans)  of  the  Triassic  sandstones 
are  by  no  means  numerous.  The  Posidonia  (Estheria)  minuta  is 
regarded  as  a  characteristic  fossil  of  this  series,  and  occurs  in  North 
Carolina.  Fig.  166  represents  several  species  of  forms  allied  to  the 
Posidonia.  In  North  Carolina,  and  also  in  Massachusetts,  the  most 
common  fossils  belong  to  the  vegetable  kingdom.  Of  these  an 
interesting  family  of  plants  are  well  known,  as  Cycades,  which  are 
among  the  vegetable  products  of  Australia. 

The  plants  represented  in  the  plates  168,  169,  are  regarded  by 
Professor  Heer  as  indicative  of  the  Keuper,  the  upper  mass  or 
division  of  the  Trias,  and  they  are  particularly  noted  as  being  infra 
Liassic,  which  is  a  very  important  fact,  inasmuch  as  they  belong  to 
the  superior  mass,  and  are  widely  separated  from  the  Chatham 
series  by  sandstones  and  conglomerates.  These  facts  give  charac- 
ter to  the  conclusion  that  the  Chatham  series  represent  a  part  of 
the  Permian  system.* 

Other  plants,  belonging  to  the  Lepidodendron  and  ancient  coni- 
fers, are  not  uncommon  in  the  plant-beds  of  the  Trias,  and  a  cha- 
racteristic one  is  probably  (fig.  172)  an  Albertia  latifolia  ? 


See  Note  B,  page  280. 


TRIASSIC   SYSTEM. 
Fig.  166. 

ENTOMOSTRACEANS  OF  THE  BUNTER  SANDSTONE. 

2 


191 


1.  Myopia  pekinensis.    2.  Cypris.    6.  Myopia  curta.    4, 3.  P^suonia  (Estlieria).     5.  Stylorhyn- 
chus  unsymmetricus.    7.  Posidonopia  rhomboidea. 

Fig.  167. 
FISH  REMAINS. 


1.  Scales  of  the  Eabdiolepis  elegans,  E.    2.  Cranial  bone.    3.  Bone  of  the  Rabdiolepia. 


192 


MANUAL   OP   GEOLOGY. 


Fig.  168. 
PLANTS  OF  THE  TRIAS. 


Neuropteris  ellingtonensis. 


Strangerites  otiliquus,  E. 


Pterozamiteg  obtnsus,  E. 


TRIASSIC    SYSTEM. 

Fig.  1C9. 
PLANTS  OP  THE  TRIAS. 


193 


Gutbieria  Carolincnsis,  £. 


Pterozapiites  obtusifolius,  E. 


Pterozamites  spatulatus,  E. 

There  are  three  important  localities  which  furnish  plants :— 1.  The  quarry  of 
Mr.  House,  of  Haywood,  situated  about  one  mile  from  the  village,  upon  the  Haw 
River.  2.  Lockville,  formerly  known  as  Jones's  Falls,  upon  Deep  River.  3. 
Ellington's,  about  five  miles  west  from  Lockville.  The  slates  which  contain  them 
are  usually  dark  colored,  but  not  bituminous,  though  at  Ellington's  there  is  a 
seam  of  bituminous  coal  about  two  inches  thick.  These  beds  are  immediately 
above  beds  of  conglomerates,  or  else  interlaminated  with  them.  No  animal  re- 
mains, as  fish  scales,  the  estheria,  or  mollusks,  have  yet  been  found  associated 
with  them.  Similar  beds  occur  only  at  other  points  in  the  valley  of  Deep  River, 
far  above  the  bituminous  slates,  which  furnish  coal,  and  the  remains  of  the  Clep. 
sisaurus,  Rutiodon,  &c. 
17 


194 


MANUAL   OF   GEOLOGY. 


Fig.  170. 
PLANTS  OF  THE  TRIAS. 


Pterozamites  gracilia.  E. 


Pteroiamites  peotinatua.  E. 


TRIASSIC    SYSTEM. 


195 


Fig.  171. 
PLANTS  OF  THE  TRIAS. 


Taxodites  brevifolia,  E. 


Lepidodeudron. 


Walehia  variabilia.  E. 


Taxodites  gracilis.    (Enlarged  one-halt) 


196 


MANUAL  OF  GEOLOGY. 


Fig.  172. 
PLANTS  OF  THE  TRIAS. 


Albeiti&latifoliaf 


TRIASSIC    SYSTEM.  197 

Fossil  ferns  are  equally  common,  and  sometimes  they  are  found 
with  fruit  dots. 

The  epoch  of  the  New  Red  Sandstone,  or  Trias,  terminated  in 
numerous  disturbances  of  the  earth's  crust,  for  in  Europe  as  well 
as  in  this  country  the  fine  sediments  are  interlaminated  with  coarse 
gravels,  and  frequently  these  beds  contain  large  blocks  of  angular 
rocks,  or  those  which  are  only  partially  rounded.  Beds  of  con- 
glomerate, made  up  of  stones  of  the  size  used  in  paving  streets,  are 
by  no  means  uncommon.  There  is  therefore  strong  evidence  that 
the  oscillations  of  the  earth's  crust  were  of  common  occurrence, 
and  led  to  a  frequent  change  of  level,  and  of  course  to  a  change  in 
the  direction  of  rivers  and  currents. 

169.  In  connection  with  these  physical  changes  the  student  will 
find  the  formation  traversed  by  the  pyroplastic  rocks,  greenstones, 
porphyries,  and  amygdaloids.      Igneous  outbursts  were  therefore 
common,  and  were  probably  the  direct  causes  which  produced  the 
oscillations  of  the  earth's  crust,  already  referred  to. 

We  therefore  regard  the  Triassic  epoch  as  one  distinguished  for 
the  phenomena  we  have  referred  to.  The  formation  of  rock  salt 
and  gypsum  were  undoubtedly  connected  with  these  disturbances, 
giving  origin  to  extensive  isolated  sheets  of  water,  where  evapora- 
tion of  sea-water  furnished  beds  of  salt  and  gypsum. 

170.  At  the  close  of  the  Triassic  we  find  several  genera  of 
fossils  which  are  common  to  the  Palaeozoic  division ;  for  example  : 
the  Cyrtoceras,  Orthoceras,  Goniatites,  Murchisonia,  Euomphalus, 
and  Porcelia.     In  the  Trias  we  find  the  following  genera,  which 
make  their  first  appearance  here,  and  finally  become  common  in  the 
Mesozoic  division,  viz. :  Ammonites,  Belemnites,  Cardita,  Trigonia, 
Ostrea,  and  Plicatula. 

The  association,  then,  of  the  older  genera  with  the  newer  ones, 
which  soon  prevail  to  a  great  extent  in  the  Mesozoic  division,  serves 
to  efface  the  sharper  lines  of  distinction  which  had  hitherto  pre- 
vailed respecting  these  two  great  periods  in  the  earth's  history.* 


*  The  Clathropteris  rectiusculus,  H.,  discovered  by  Prof.  Hitchcock  at  East 
Hampton,  towards  the  upper  part  of  this  series,  does  not  prove  that  the  pnrt  in 
which  it  was  found  belongs  to  the  Jurassic ;  it  differing  specifically  from  the  Jurassic 
species  of  Europe;  inasmuch,  too,  as  the  genus  belongs  also  to  the  Triassic  sys- 
tem. Hence  it  would  be  as  consistent  to  claim  this  plant  for  the  latter  as  for  the 
former  system. 

17* 


CHAPTER  XVII. 

JURASSIC  SYSTEM — IMPERFECTLY  REPRESENTED  IN  THIS  COUNTRY 

ITS  POSITION  ON  THE    CONTINENT  OP  EUROPE ITS  SAURIAN 

REMAINS — CHARACTER  OF  THE  SEDIMENTS — DIVIDED  INTO 
FIVE  STAGES — THE  LIAS  HAS  THREE  GROUPS — THE  \VEALDEN 
CLOSES  THE  EPOCH. 

171.  So  little  is  known  of  the  Jurassic  system  in  this  country, 
that  we  prefer  to  describe  very  briefly  the  European  series,  as  this 
epoch,  as  we  find  it  here,  is  only  imperfectly  represented.  In 
certain  points  of  view,  it  is  interesting,  as  well  as  important.  It 
occupies  a  central  position  on  the  Continent  of  Europe,  being  well 
developed  in  the  Jura  Mountains,  lying  between  France  and 
Switzerland ;  especially  the  Liassic  stage,  which  is  regarded  as  the 
argillaceous  base  of  the  system. 

It  is  in  this  system,  that  Saurians  attained  a  maximum  develop- 
ment of  this  class  of  vertebrates ;  they  were  both  numerous,  and 
of  immense  size.  Two  very  remarkable  genera  have  been  de- 
scribed in  almost  every  treatise  upon  geology,  viz. :  the  Icthyo- 
saurus,  and  Plesiosaurus ;  the  former  is  distinguished  by  a  short, 
and  the  latter  by  a  long  neck.  These  reptiles  were  aquatic  or 
marine,  and  were  furnished  with  paddles  of  great  power,  for  moving 
swiftly  through  the  water.  The  eyes  of  the  Icthyosaurus  were 
large,  and  furnished  with  peculiar  envelopes,  or  a  special  appa- 
ratus, which  enabled  them  to  adapt  the  vision  to  the  distance  of 
the  object  it  wished  to  see.  The  Teleosaurus,  another  genus 
belonging  to  this  epoch,  was  furnished  with  legs,  instead  of  paddles, 
and  in  its  general  appearance,  resembled  the  Gavial  of  the  Ganges. 
It  was  in  this  epoch,  also,  that  flying  lizards,  or  Pterodactyles,  seem 
to  have  been  common,  and  to  have  contributed,  by  their  organiza- 
tion and  habits,  to  its  singularity.  In  the  organization  of  the  rep- 
tiles of  this  epoch,  it  is  easy  to  recognise  in  the  Saurian  type,  the 
bird,  fish,  and  cetacean. 

(198) 


JURASSIC    SYSTEM. 


199 


The  sediments  of  this  epoch  are  fine,  and  well  adapted  to  the 
preservation  of  fossils ;  and  to  this,  we  may  attribute  much  of  the 
exact  knowledge  we  have  obtained  of  the  peculiar  animals,  and  of 
their  organization.  Frequently,  their  skeletons  are  entire,  or  their 
parts  so  closely  united,  that  it  has  not  been  difficult  to  restore  their 
exact  forms. 

172.  The  Jurassic  system  has  been  subdivided  into  five  stages  : 
the  Lias,  Lower  Oolite,  Oxfordian,  Upper  Oolite,  and  the  Wealden 
series.  The  whole  series,  in  Europe,  has  a  thickness  of  about 
1030  feet. 

The  Lias  is  divided  into  three  groups:  the  Lias  Inferior,  the 
Middle  and  Upper  Lias.  The  passage  from  the  New  Red  to  the 
Lower  Lias,  is  quite  distinct.  The  latter  consists  of  a  fine  white, 
micaceous  sandstone,  which  often  abounds  in  the  remains  of  fishes; 
hence,  it  is  blackened  by  animal  matter,  in  the  form  of  bitumen, 
and  though  the  stratum  is  thin,  it  is  recognisable  over  large  terri- 
tories. The  Grryphea  arcuata,  fig.  174,  2,  is  one  of  the  character- 
istic fossils.  The  Middle  Lias,  is  a  blue  argillaceous  limestone, 
often  striped,  and  abounds  with  fossils,  as  the  Spirifers,  Pentacri- 
nites,  Pectens,  Ammonites,  and  Fish;  among  which  are  recognisea 
the  genus  Tetragonolepis,  fig.  173,  and  an  Ichthyodolerite  of  the 
genus  Hybodus,  fig.  194,  1.  The  Upper  Lias  consists  of  a  dark- 
colored  shale,  particularly  at  Whitby,  in  England,  and  has  been  em- 
ployed in  the  manufacture  of  alum. 

Fig.  173. 


Tetragonolepis. 


194—1. 


200 


MANUAL   OF   GEOLOGY. 


Fig.  174. 
JURASSIC  FOSSILS. 


Trigonia. 


Ammonites  j 


Aucyloceras  matheroniensis. 


JURASSIC    SYSTEM. 


201 


The  Lower   Oolite  consists  of  alternating  Fig.  175. 

masses,  or  bands  of  limestones  and  clays.  The 
particles  forming  the  limestone,  have  the  ap- 
pearance not  unlike  the  roe  of  fish,  and  hence 
the  name  Oolite.  The  Lower  Oolite  contains 
good  building  materials,  and  some  inferior 
iron  ores.  This  group  is  made  up,  in  Eng- 
land, of  Inferior  Oolite,  Fuller's  earthy 
Stonesfield  slate,  Brad  for  delay,  Great  Oolite, 
Forrest  marble,  and  Cornbrash. 

The  group  of  Middle  Oolite  consists  of  five 
members :  Kelloway  rock,  Oxford  clay,  lower 
calcareous  grit,  coral  rag,  and  upper  calcareous 
grit.  The  group  contains  Gryphea  dilatata 
Ammonites  jason.  The  Upper  Oolites  con- 
sist of  Kimrneridge  clay,  Portland  sand,  and 
Portland  stone. 

The  Wealden  series  brings  the  Jurassic 
system  to  a  close.  It  is  mostly  a  fresh  water 
deposit,  and  is  more  fully  developed  in  Eng- 
land than  on  the  Continent.  It  consists  of 
the  Purbeck  beds,  Hastings  sand,  and  the 
Weald  clay.  The  fossils  of  this  period  are 
Unios,  Cythere,  and  gigantic  bones,  belong- 
ing to  an  herbivorous  land  reptile,  the  Igua- 
nodon,  whose  remains  are  also  associated  with 
an  enormous  carnivorous  reptile,  the  Mega- 
losaurus.  The  beds  which  are  described  in 
the '  preceding  paragraphs,  as  forming  the 
Wealden,  are  now  referred,  by  several  accom- 
plished geologists,  to  the  Lower  Cretaceous; 
and  it  should  be  observed,  that  Prof.  Leidy  has  recognised  fossils  in 
this  group,  which  indicate  the  existence  of  the  Wealden  in  Nebraska 

The  Jurassic  system  is  not  represented  in  this  country  by  the 
presence  of  all  the  European  members,  though,  in  the  far  West, 
future  investigations  may  prove  that  it  is  as  fully  developed  as  in 
the  chain  of  the  Jura. 

The  annexed  section,  fig.  175,  is  designed  to  show  its  relations, 
as  it  exists  in  the  region  of  the  Black  Hills  of  Nebraska. 

173.  Black  Hills  of  Nebraska. — Thus,  1.  Granite  nucleus,  around 


Section  Black  Hills  of 
Nebraska. 


202 


MANUAL   OF   GEOLOGY. 


which  the  sediments  have  been  deposited.  2.  Metamorphic  sedi- 
ments, probably  the  Taconic  system.  3.  Potsdam  sandstone,  the 
only  visible  member  of  the  Silurian  system,  and  resting,  uncon- 
formably,  upon  the  Taconic  series.  4.  Carboniferous  system,  con- 
sisting of  gray  limestones  and  reddish  grits.  5.  Permian  system. 
6.  Jurassic,  consisting  mainly  of  the  Liassic  stage.  7.  Creta- 
ceous. The  Liassic  series  of  this  locality,  consist  of  shaly  beds 
of  dark  brown,  and  also  yellowish  sandstones,  containing  Belemnites, 
Pentacrinites,  an  Avicula,  and  an  Area,  of  Jurassic  types. 

The  vegetable  fossils  of  the  Jurassic  system,  consist  of  Zamias  and 
Cycadeas,  resembling  those  which  illustrate  the  New  Pted  Sandstone 
of  the  preceding  chapter. 

174.  Distribution  of  the  Jurassic  System. — The  geographical 
area  occupied  by  this  system  is  not  determined.  It  is,  however, 
supposed  to  extend  along  the  eastern  slope  of  the  Rocky  Mountains, 
from  the  northern  part  of  the  British  possessions  in  America,  to 
New  Mexico.  It  has  also  been  recognised  upon  the  head  waters 
of  the  Yellowstone. 

It  is  unknown  upon  the  Atlantic  slope;  at  least  the  evidence  of 
its  existence  is  not  reliable. 


Liassic  Fauna  and  Flora  regt  .red. 
1.  Flegiosaurus.     2.  Ichtbyosau  us.    3,  5.  Pterodactyle.    4.  Cycad,  ic. 


CHAPTER  XVIII. 

CRETACEOUS  SYSTEM — CHARACTERISTICS  OF  THE  MESOZOIC  DIVI- 
SION— DERIVATION  OF  THE  NAME  CRETACEOUS — LOWER  DIVI- 
SION— THE  GREEN-SAND  LITHOLOGICAL  CHARACTERS — FOSSILS 
OF  THE  GREEN-SAND. 

* 

175.  THE  Mesozoic,  which  closes  with  this  system,  presents  such 
peculiar  aspects  that  its  separation  from  the  Palaeozoic  and  Caino- 
zoic  was  justifiable.  This  separation  is  based  upon  its  flora  and 
fauna,  particularly  the  latter.  At  this  day  it  is  safe  to  assume  that 
this  division  is  sufficiently  examined  to  assure  us  that  we  know  its 
leading  characteristics,  which  may  be  summed  up  in  a  few  words. 
In  its  early  stages  reptilian  forms  of  life  were  its  most  striking 
features.  They  stood  out  in  such  bold  relief  that  they  have  been 
called  the  master  existences  of  that  age.  We  may  refer  to  the 
Enaliosaurs  of  the  Lias,  and  the  Labyrinthodonts  of  the  Trias. 
These,  however,  have  all  passed  away,  with  the  massive  Megalo- 
saurs  and  Iguanodon  of  a  later  period  in  this  division  of  geologic 
time.  But  this  division  is  also  noted  for  the  absence  of  mammals, 
excepting  those  which  are  of  small  dimensions.  This,  we  say,  must 
be  received  as  a  striking  fact,  not  resting  on  conjecture,  for  reliable 
observations  establish  the  abundance  of  reptiles,  fish,  and  mollusks 
of  forms  peculiar  to  this  period,  while  the  mammals,  if  they  had 
occupied  a  prominent  rank  in  this  ancient  fauna,  would  have  been 
also  brought  to  light.  It  is  true,  that  within  the  last  eighteen 
months  quite  an  addition  has  been  made  to  the  list  of  small  mam- 
mals, no  less  than  fourteen  species  having  been  added  from  the 
Purbeck  beds  of  England,  some  of  which  are  closely  allied  to  the 
Marsupials,  which  occupy  a  low  grade  in  this  class.  This  is  a  sig- 
nificant fact  in  itself. 

These,  however,  dwindle  into  insignificance,  when  compared  with 
Ihe  hosts  of  marine  and  land  reptiles,  which  were  truly  the  master 
vertebrates  of  this  epoch.  With  this  division,  too,  we  find  one  of 
the  ranks  of  fish — the  Ganoids — diminishing  in  importance  near 

(203) 


204  MANUAL  OF   GEOLOGY. 

its  close.  While,  at  the  same  time,  the  Ctenoids  and  Cycloids,  two 
new  classes,  begin  their  existence,  which  are  destined  to  fill  a  wide 
space  in  our  own  time.  In  the  last  series  of  the  Mesozoic  age  the 
cretaceous  rocks,  the  dying  out  or  extinction  of  many  races  which 
had  before  been  strong  and  powerful,  the  introduction  or  creation 
of  classes  destined  to  multiply  upon  the  earth,  to  make  up  in  num- 
bers for  the  lack  in  force  and  individual  strength,  are  great  and 
significant  facts  of  the  period.  Dynasties  come  to  a  close  with  the 
cretaceous,  and  dynasties  begin  ;  but  they  simply  foreshadow  their 
reign  during  the  last  third  of  the  cretaceous  system.  We  reach 
the  same  general  results  from  a  consideration  of  the  vegetable  king- 
dom. It  is  only  at  the  close  of  this  system  that  .dicotyledonous  trees, 
those  which  bear  our  favorite  fruits  and  flowers,  begin  to  make  their 
appearance.  They  were  created  almost  contemporaneously  with  the 
Ctenoids  and  Cycloids,  the  great  classes  from  which  we  cull  the 
favorite  fish  for  our  tables.  Surely,  such  facts  are  not  to  be  ranked 
as  accidents. 

176.  This  system  derives  its  name  from  the  well-known  sub- 
stance, white  chalk,  used  so  extensively  in  marking.  It  is  subdivided 
into  Lower  and  Upper  Cretaceous  groups,  which  differ  materially  in 
their  lithological  characters. 

The  lower  group  is  widely  known  as  the  Green-sand,  and  in  many 
places  simply  as  marl,  as  in  New  Jersey. 

This  group  consists  of  six  members,  the  most  important  of  which 
are  those  beds  of  Green-sand  (omitting  the  potter's  clay  beneath), 
which  are  separated  by  intervening  beds  of  sand  of  various  colors. 
The  name  of  the  Lower  Cretaceous  group  is  derived  from  small 
rounded  particles  of  a  green  color,  of  the  size  of  coarse  gunpowder, 
and  which  consist  mainly  of  silicate  of  iron.  These  are  so  nume- 
rous that  a  green  color  is  frequently  imparted  to  the  bed.  There  is 
but  a  slight  difference  in  the  mineralogical  characters  of  the  three 
beds,  though  the  upper  contains  fossils  which  do  not  occur  in  the 
lower.  The  lower  or  first  bed  of  Green-sand  supports  a  bed  of  reddish 
or  yellowish  sand  quite  ferruginous ;  and  so  the  second  supports  a 
sand  bed  similar  to  that  upon  a  sea  beach.  Although  the  presence 
of  green  grains  will  not  in  certain  cases  be  sufficient  to  distinguish 
this  part  of  the  series  from  other  rocks,  as  there  are  many  locali- 
ties where  the  green  grains  have  been  carried  up  into  the  Miocene 
beds.  The  fossils,  however,  are  quite  characteristic  of  the  forma- 
tion. The  lower  bed  contains  Exogyra  costata,  fig.  176  (1),  Tere- 


CRETACEOUS   SYSTEM. 

Fig.  176. 
FOSSILS  OF  THE  GREEN-SAND. 


205 


1.   Exogyra  costata.    2.   Cuculea  vulgaris    (cast).    3.  Terebratula   Sayi.    4.    Torebratula  fragilis.    3 
Janira  quinquecostata  (Neooomian).  6.  Pecten  quadricostata.  7-  Terebratula  Harlani.    8.  Os 

18 


206 


MANUAL  OP  GEOLOGY. 
Fig.  177. 


Belomnitella  Americana  (Morton). 


Belemnitella  compressa,  £. 

bratula  Sayi,  (3);  Ostrea  falcata,  (8) ;  Terebratula 
Harlani,  (7),  and  T.  fragilis,  (4);  Cucullea  vulgaris, 
(2);  Janira  quinquecostata,  (5);  Pecten  quadricos- 
tatus,  (6). 

In  North  Carolina  the  Green-sand  admits  of  the 
same  division  as  those  which  have  been  pointed  out 
by  Professor  Cook,  of  New  Jersey,  but  it  is  believed 
that  the  lower  bed  does  not  come  to  the  surface; 
and  besides,  the  fossils  are  less  numerous  than  in 
New  Jersey,  and  the  marl  itself  contains  a  larger 
proportion  of  sand.  The  lowest  bed  upon  Cape  Fear 
is  sandy  below,  and  argillaceous  above,  and  supports 
a  thin  bed  of  white  Miocene  marl,  the  Eocene  being 
absent. 

177.  The  following  scries  Illustrates  the  relations  of  the 
Lower  Cretaceous  rocks  in  New  Jersey  and  North  Carolina. 
(Fig.  178.) 

1.  Fire  clay  of  Woodbridge,  N.  J.,  or  pure  potter's,  with  sands 
and  clays  of  various  colors,  resting  upon  the  Triassic  series. 
2.  Green-sand.  3.  Sand-colored  brown,  yellow,  Ac.  4.  Green- 
sand.  5.  White-sand.  6.  Upper  Green-sand.  7.  Sand  and 
shell  marl  miocene.  8.  Sand. 

Fig.  179.  Section  upon  Cape  Fear  Kiver,  N.  C.  1.  Marine 
sand.  2.  Brown  earth.  3.  Brick  clay.  4.  Sand.  6.  Shell 
marl.  6,  7,  8.  Green-sand.  The  upper  bed  is  argillaceous,  and 
supports  a  thin  bed  of  Miocene  marl.  The  Eocene  is  absent  in 
numerous  places. 


CRETACEOUS    SYSTEM.  207 

Fig.  179. 


178.  In   Alabama  we  find  the   Cretaceous  represented  at  the 
Prairie  Bluff  limestone,  which   consists,  1st,   mainly  of  a  white 
limestone,  containing  the  Exogyra  costata,  Voluta  Sayana,  Pecten 
5  costatus.     Beneath  this,  or  2d  place,  is  a  white  sand,  about  forty 
feet  thick,  in  which  are  numbers  of  the  Ostrea  larva,  Gryphea  vomer, 
and  Pecten  5  costatus.     3d,  Rotten  limestone,  with  Cucuella  vul- 
garis ;  and,  4th,  Concrete  and  loose  sand,  sand  and  clay,  containing 
drift-wood,  as  at  Choctaw  Bluff,  &c. 

179.  Extent  of  the  Cretaceous  Rocks,  and  summary  of  the  lead- 
ing/acts relative  to  the  formation. — The  Cretaceous  rocks  of  New 
Jersey,    Delaware,    Virginia,  North   and   South    Carolina   appear 
in  rather  isolated  patches,  but  still  they  are  probably  continuous 
and  connected  deposits.     In  Alabama  the  formation  is  more  ex- 
tended, and  in  the  Valley  of  the  Mississippi  they  occupy  a  wide 
extent  of  country.     Some  of  the  most  important  fossils  belong  to 
the  vertebrate  class.    A  Mammifer,  belonging  to  the  seals ;  Saurians, 
as   the    Mosasaurus;   teeth  of  sharks,  the  Laranas  and  Charcha- 
rias,  Cephalopods  in  great  abundance,  as  Belemnitellas,  Ammonites, 
Baculites,  Brachiopods,  or  Terebratulas,  &c. 

The  Mosasaurus,  fig.  180 — 2,  was  once  regarded  as  belonging 
to  a  distinct  genus,  but  Saurian  teeth  vary  much  in  form  as  well 
as  size.  The  Hadrosaurus,  180 — 6,  was  an  enormous  Saurian 
closely  allied  to  the  Iguanodon  of  Wealden.  The  genus  Polypto- 
chodon  is  also  found  in  England. 


MANUAL   OF   GEOLOGY. 


Fig.  180. 
FOSSIL  SAURIANS. 


I,  2.  Toeth  of  the  Mosasaurns.    3.  Polygonodon  rectns  (L,eidy).  4.  Pristis  of  the  Eocene.   5,  5.  Sec- 
tions of  the  Mosasaurus.    6.  Hadrosaurus  Foulkii  (Leidy).    7.  Polyptychodon  rugosua,  E. 


CHAPTER  XIX. 

CAINOZOIC  DIVISION — GENERAL  CHARACTERISTICS  OF  THIS  DIVI- 
SION— SIR  CHARLES  LYELL's  SUBDIVISIONS  OF  THE  TERTIARY — 
EOCENE,  MIOCENE,  AND  PLIOCENE,  ETC. 

180.  WHEN  the  length  of  the  three  great  divisions  is  computed 
by  the  amount  of  the  accumulated  sediments,  the  fact   that  these 
divisions  are  of  very  unequal  length,  is  quite  striking.     The  sedi- 
ments of  the  Palaeozoic  divisions  are  enormously  thick.     When, 
however,  we  compare  them  with  respect  to  their  organic  contents, 
the  Palaeozoic  fossils  are  insignificant,  or  occupy  comparatively  a 
low  rank,  when  placed  by  the  side  of  the  Cainozoic  representatives. 
Up  to  the  close  of  the  Cretaceous,  no  imposing  structure  belonging 
to  the  mammal  class  had  appeared,  but  immediately  after,  or  at  the 
beginning  of  the  Cainozoic  time,  herds  of  large  mammals  appear 
upon  the  stage.     There  are  Pachyderms,  herbivorous  quadrupeds, 
whose  remains  have  been  disinterred  from  the  plaster  of  Montmartre, 
near  Paris.     Mammals,  then,  at  once  assume  an  importance.     The 
reptiles,  though  numerous,  have  lost  their  standing  as  masters  of 
existence;  and  from  this  epoch,  onward  to  the  present,  the  mammals 
increase  in  power  and  rank,  until,  finally,  man  appears  upon  the 
scene,  the  lord  of  this  lower  creation. 

The  aspect  which  the  Tertiary  epoch  presents,  distinguishes  it, 
clearly,  from  all  that  had  preceded  it.  It  is  not  imagination,  it  is 
not  theory,  that  these  views  are  based  upon ;  but  observation,  carried 
on  in  all  parts  of  the  earth.  It  is  a  deduction  from  facts,  which 
point  only  in  one  direction,  and  which  lead  to  the  conclusions  which 
we  have  stated. 

Sir  Charles  LyelPs  division  of  the  Tertiary  still  commends  itself 
to  the  student  for  its  simplicity. 

181.  This  general  threefold  division  into  Eocene,  Miocene,  and 
Pliocene,  requires  attention.     In  the  first  place,  the  divisions  are 
determined  by  the  numerical  ratios  which  the  extinct  species  in  any 
given  bed  bear  to  the  living.     The  Eocene  expresses  the  dawn  of 

18*  (209) 


210  MANUAL   OF   GEOLOGY. 

the  present;  hence,  the  ratio  of  the  extinct  species  to  the  living 
ones  is  very  large,  or  rather,  the  living  species  in  the  Eocene  are 
very  small,  if  compared  with  extinct  ones.  About  four  or  Jive  per 
cent,  only  of  the  fossils  of  the  Eocene  live  upon  the  earth  or  in  the 
sea  at  the  present. 

In  the  older  Miocene,  seventeen  to  forty  per  cent,  of  the  species 
are  living  now.  While  in  the  Pliocene,  or  full  dawn,  the  living  spe- 
cies vary  from  forty  to  ninety-five.  Hence,  the  relative  age  of  the 
Tertiary  beds  is  determined  by  a  comparison  of  their  enclosed 
fossils,  with  those  which  live  at  the  present  time. 

These  divisions  admit  of  subdivisions,  as  Lower,  Middle,  and 
Upper,  by  which  closer  comparisons  become  practicable.  It  may 
appear,  to  the  student,  that  the  classification  of  the  Tertiary  is  too 
artificial  and  arbitrary,  and  is  wanting  in  philosophical  principles. 
This  is  far  from  being  the  case.  Under  its  artificial  dress,  it  covers 
principles  of  the  highest  importance. 

182.  It  is  found  that  the  most  recent  beds  contain  the  remains 
of  animals  and  plants,  all  of  which  are  species  whose  identity  with 
the  living  is  fully  established.    If  we  go  back  one  stage,  the  identity 
of  only  ninety-five  per  cent,  is  established ;  and  if  we  go  back  still 
another  stage,  the  ratio  of  the  extinct  to  the  living  is  still  greater. 

It  is  a  consequence,  then,  perhaps  too  plain  to  require  a  state- 
ment, that  the  relative  age  of  a  bed  is  fixed  when  the  ratio  of  the 
extinct  to  the  living  is  determined ;  the  nearer  it  is  to  the  present, 
so  much  greater  will  be  the  ratio  of  its  remains  to  those  of  our 
own  times,  and  the  less  the  ratio,  the  further  removed  it  will  be. 
Following  out  this  idea,  we  soon  reach  a  stage  in  our  recession, 
when  the  present  is  unrepresented  by  living  species.  The  resem- 
blance becomes  generic,  on  receding  still  farther  in  time,  or,  on 
reaching  the  Palaeozoic  period,  the  generic  resemblance  becomes  too 
faint  to  be  confidently  asserted.  The  great  and  leading  divisions 
of  the  Kingdoms  of  Nature,  however,  are  still  fixed,  and  strong, 
and  as  clearly  distinguishable  as  at  the  present  time.  There  are  no 
monsters — no  unclassifiable  beings,  who  refuse  to  submit  to  the  sys- 
tematic arrangement  of  the  zoologist  and  botanist ;  all  is  consistent, 
and  in  harmony  with  the  present,  though  the  genera  and  species 
of  the  present  have  disappeared  in  our  retrospect  of  the  past. 

183.  The  Tertiary  consists  of  marine  and  freshwater  deposits, 
which  are  frequently  confined  to  separate  basins ;  and  though  they 
are  sometimes  spread  over  wide  areas,  yet  they  possess  more  of  a 


CAINOZOIC  DIVISION.  211 

local  character  than  the  older  formations.  The  chronology,  in  each 
case,  is  determined  by  the  considerations  and  principles  just  stated. 
Our  Atlantic  coast  furnishes  an  example,  over  which  the  Tertiaries  are 
widely  spread,  and  probably  the  Valley  of  the  Mississippi  and  eastern 
slope  of  the  Rocky  Mountains  are  equally  remarkable  for  the  breadth 
and  length  of  these  more  modern  formations.  On  the  contrary,  the 
London  and  Paris  basins  are  comparatively  circumscribed,  and  yet 
have  given  law  to  our  modes  of  investigation. 

184.  As   a  whole,  the  fossils  of  the  Cainozoic   division   bear  a 
stronger  resemblance  to  those  which  now  live  than  those  belonging 
to  the  preceding  periods. 

The  lithological  characters  of  the  basins,  and  estuaries,  &c., 
must,  of  course,  present  great  differences,  and  hence  are  not  de- 
pended upon  to  determine  their  ages.  They  repose  upon  rocks  of 
all  periods,  from  the  oldest  to  those  which  immediately  precede 
their  own.  A  difficulty  is  met  with  in  the  investigation  of  the 
Tertiary,  especially  in  settling  its  chronology,  which  should  be 
noticed  in  this  place.  It  arises  from  the  limited  distribution  of 
species,  or  their  confinement  to  particular  seas,  estuaries,  &c. 
Thus,  the  fauna  of  the  Red  Sea  differs  materially  from  that  of  the 
Mediterranean ;  so  the  influence  of  a  particular  sediment  greatly 
influences  the  character  of  the  animals  which  inhabit  the  area  over 
which  it  prevails.  Certain  species  live  upon  a  muddy  bottom ; 
others,  upon  a  sandy  one ;  and  the  formation  of  these  bottoms  may 
have  been  simultaneous,  and  yet  their  faunas  differ.  But  this 
kind  of  influence  is  not  confined  to  the  Tertiary  deposits. 

But  we  remark  again,  leaving  out  of  the  view  the  difficulties 
set  forth  in  the  foregoing  paragraphs,  it  has  been  found,  by  actual 
experience,  that  the  divergences  of  a  fauna  from  the  present  ones, 
of  any  country  we  may  select,  has  so  many  advantages  in  settling 
the  chronology  of  a  particular  basin  or  a  series  of  beds,  that  it  can- 
not at  present  be  dispensed  with. 

185.  The   Eocene  Formation  of  the  Atlantic  Slope. — Litho- 
iogically,  it  has  no  unity  of  character. 

On  James  river,  the  Eocene  resembles,  mineralogically,  the  Green- 
Band.  In  North  Carolina,  the  Eocene  consists  of  white,  soft 
inarls,  sometimes  tinged  brown  or  drab.  Beds  of  the  same  age 
are  consolidated,  and  become  white  limestone,  as  upon  the  Neuse, 
twenty  miles  above  Newbern.  They  rest  on  soft  marls,  and  the  upper 
layers  are  frequently  soft,  also.  These  consolidated  beds  are  often 


212  MANUAL   OE   GEOLOGY. 

silicious,  and  filled  with  rounded  grains  of  sand.  They  rarely 
contain  over  seventy-five  per  cent,  of  lime.  Higher  up,  on  the 
Neuse,  in  Wayne  county,  these  consolidated  beds  are  associated 
with  a  light,  laminated  material,  which  would  be  suspected  to  con- 
sist of  infusorial  matter.  It  is,  however,  merely  fine  silex,  with  a 
very  small  proportion  of  calcareous  matter. 

Similar  beds  of  Eocene  exist  at  Wilmington,  charged  with  the 
same  kind  of  fossils  as  those  at  and  near  Newbern. 

Between  the  Grove  and  Vance's  Ferry,  on  the  Santee  river,  S. 
C.,  there  is  a  continuous,  white  soft  limestone,  extending  forty 
miles,  which  belongs  to  this  formation. 

Upon  the  Savannah  river,  forty  miles  below  Augusta,  the  white, 
indurated  marlj  together  with  the  soft  marls,  are  overlaid  with  red 
clays  and  loam.  The  formation  seems  to  be  completed  by  a  depo- 
sition of  silicious  beds,  which  have  been  called  the  Georgia  buhr- 
stone.  Like  the  Paris  buhrstone,  it  has  a  rough  appearance,  and 
has  many  cavities.  It  passes  into  a  sandstone  with  geodes,  lined 
with  crystals.  Often,  the  interior  of  these  geodes  are  agatized, 
and,  in  fine,  passes  into  cacholong.  Fine  specimens  of  opal  are 
occasionally  found. 

The  Eocene  of  Alabama  is,  perhaps,  more  perfectly  developed  than  in  North 
and  South  Carolina,  particularly  at  St.  Stephen's  and  Clairbourne.  In  the  descend- 
ing order  we  find  the  following  beds.  1.  The  superficial  materials  of  recent  ori- 
gin. 2.  White  Eocene  limestone  at  St.  Stephen's  and  Clairbourne,  containing 
Plagiostonaa  dumosum,  Pecten  Poulsoni,  Scutella  Lyellii,  and  bones  of  the 
Zeuglodon.  3.  Bluish,  buff,  and  green-colored  sands,  containing  Cardita  plani- 
costata,  &c.  4.  A  kind  of  buhrstone;  a  silicious  porous  rock,  probably  a  fresh- 
water deposit.  5.  Buff-colored  sands,  clay  and  limestone.  This  is  the  base  of 
the  Eocene,  and  reposes  upon  the  Prairie  Bluff  limestone  which  is  equivalent  to 
the  green-sand,  as  it  contains  Exogyra  costata,  &c.  These  sands  have  numerous 
fossils  which  differ  from  those  found  at  St.  Stephen's  and  the  superior  beds  of 
Clairbourne.  At  Vicksburg,  on  the  Mississippi,  the  Eocene  beds  correspond 
with  the  upper  Eocene  at  Clairbourne  and  St.  Stephen's. 

Foreign  Localities. — Paris  basin  and  London  clay.  Isle  of  Wight. 
The  first  consists  of  Upper  and  Lower,  or  the  millstone  above,  the 
gypseous  beds  below,  which  contain  the  Palseotheria,  Anoplo- 
theria,  Didelphis,  and  many  other  quadrupeds.  The  London  clay 
corresponds  to  the  Calcaire  grosier,  of  the  Paris  basin.  Both  are 
rich  in  univalve  and  bivalve  mollusks. 

186.  Extent  and  Summary  of  Facts. — The  Eocene  exists  in 
Texas,  Alabama,  Mississippi,  Arkansas,  Louisiana,  Georgia,  North 
and  South  Carolina,  Virginia,  Maryland,  and  Delaware.  Some  of 


CAINOZOIC   DIVISION. 


213 


the  beds  resemble  the  green   sand,  as  Fig.  181. 

those  near  Petersburg,  Va.  Farther 
south,  they  are  white  marls,  with  about 
seventy-five  per  cent,  of  carbonate  of 
lime,  and  from  six  to  twenty-five  per 
cent,  of  sand.  These  beds  are  fre- 
quently limestones. 

187.  Miocene. — It  consists  of  a  series 
of  strata,  which  are  clays,  sands,  and 
shell  marls,  of  white,  green,  and  brown 
colors.  The  shell  marl  in  the  South, 
exists  only  in  isolated  beds  or  banks, 
similar  to  modern  oyster  banks.  They 
are  surrounded  by  sands,  and  the  shell 
banks  may  extend  a  quarter  of  a  mile, 
but  frequently  they  occupy  only  a  few 
feet  in  length.  Where  the  banks  are 
well  formed  the  bottom  is  composed  of 
a  few  pebbles — eoprolites,  with  teeth  of 
the  larger  kinds  of  sharks ;  and  hence  it 
appears,  that  the  Miocene  was  preceded 
by  oscillations  of  the  surface.  In  con- 
firmation of  this  view,  some  of  the  beds 
upon  the  Cape  Fear  contain  green-sand 
and  its  fossils,  as  the  Exogyra  costata, 
Belemnitella  Americana,  casts  of  Cu- 
cullea,  <&e. 

The  section,  fig.  184,  presents  the 
beds,  and  their  order  upon  the  Cape 
Fear,  at  Brown's  Landing. 

1.  Sand.  2.  Brown  earth.  3.  Clay, 
four  or  five  feet  thick.  4.  Sand  and 
pebbles.  5.  Shell  marl.  6,  Sand,  with 
consolidated  beds,  which  resemble  gray 
sandstone,  containing  fossils  and  lignite.  7.  Blue  clay.  8.  Sand, 
blue  clay,  succeeded  by  sand. 

Sections  of  similar  beds,  upon  the  Tar  river,  near  Tarboro,  Edge- 
combe  co.,  N.  G. 


Tooth  of  an  Eocene  Whale. 


214 


MANUAL   OF   GEOLOGY. 

Fig.  182. 
CETACEAN  OF  THE  EOCENE. 


1,  2,  3.  Different  teeth  of  the  Zeuglodon,  an  Eocene  Cetacean.         4.  Enchodus  ferox,  a  fish  of  th* 


CAINOZOIC  DIVISION. 


215 


Fig.  183. 
FOSSILS  OP  THE  EOCENE. 


TTygon  Caroline  nsis.  E. 


Nnmmulitcs  ataic 


7.  Microcriiius  conoidcus.  E. 
6.  Eohynocyamus  parvus.  E. 


Echinus  Rufiini. 


216  MANUAL   Or   GEOLOGY. 

Fig.  184. 


x 


(~~     0   .    o       <•    .    o..   .0.  .     r,   c.   -   a     .-   o    .«     «-        c~     4-. 

/5SS 

^    ft-^ 

>^  0iB     5 

/^~ 

6 

/                Z-=^ 

^~^' 

-^^^? 

-&- 


r          2. 


The  fossils  of  the  Miocene  are  quite  numerous ;  they  are  not  all 
found  at  any  one  bed.  A  few  freshwater  shells  are  not  uncommon, 
showing  that  there  was  land  in  the  immediate  vicinity. 

188.  In  the  immense  region  of  the  waters  of  the  Mississippi, 
the  Miocene  has  become  one  of  the  most  interesting  fields  for  geo- 
logical research,  of  any  in  the  United  States.  Upon  the  eastern 
slope  of  the  Rocky  Mountains,  a  large  extent  of  this  formation  is  a 
freshwater  deposit.  The  most  interesting  part  of  this  field,  is  upon 
White  river,  in  Nebraska,  embracing  all  that  part  of  the  region 
which  is  called  Mauvais  Terres.  This  formation  is  remarkable  for 
its  mammaliferous  remains  belonging  to  the  order  Pachyderms.  It 
is  the  Lower,  or  Older  Miocene. 

The  Pachyderms  of  this  period,  in  the  Miocene  of  the  Atlantic 
slope,  are  not  numerous.  The  Mastodon,  however,  is  a  common 
fossil,  together  with  the  horse  and  hog.  From  this  fact  it  follows, 
that  the  Mastodon  commenced  its  existence  here  as  early  as  in 
Europe.  Teeth,  vertebra,  ribs,  the  cuneiform  bone  of  the  foot,  &c., 
have  been  found  at  distant  points.  At  the  same  time,  it  is  true, 
the  Mastodon  is  found  in  marls  and  peat  bogs,  resting  upon  the 
upper  bed  of  the  drift  in  New  York.  Of  the  same  age^  too,  is  that 
remarkable  rodent,  Castoroides  Ohioensis.  The  earliest  appearance 
of  the  Mastodon  is  in  the  Miocene.  The  generalization,  therefore, 
which  has  been  attempted  relative  to  the  age  of  this  continent 
compared  with  Europe,  is  hasty,  and  is  not  well  sustained. 


CAINOZOIC  DIVISION. 

Fig.  185. 
MAMMALS  OF  THE  OLDER  MIOCENE. 


21' 


1.  Titanotherium  proutii  (Leidy).  Left  side  of  the  Lower  Jaw,  showing  the  triturating  surface. 
2.  Rhinoceros  nebrascensis  (Leidy;.  3.  Mylodon  Harlani,  an  extinct  Sloth.  Big  Bone  Lick.  Two- 
thirds  the  natural  size. 

19 


218 


MANUAL  OF  GEOLOGY. 
Fig.  186. 


Grinder  of  the  extinct  Horse. 


Mastodon,  Marl  Beds  of  North  Carolina. 


Incisors  of  the  Horse,  N.  C. 


Last  Mo'.ur  <>f  the  Under  J<i 
of  the  Pig,  N.  C. 


Oreodon  Cnlbertsoni  (Leidy)     a.  Kuminant,  Nebraska. 


CAINOZOIC  DIVISION. 

Fig.  187. 


219 


TestudoOweni(Leidy). 


^etus  Emmonsi  (Leidy) ;  Cetacean.    (Half  natural  size.) 


220 


MANUAL   OF   GEOLOGY. 
Fig.  188. 


Structure  of  the  Tooth  of  the  Lamna  compressa. 
(Greatly  enlarged.) 


Carcharodon  ferox ;  probably  Eocene. 


Arrangement  of  the  Teeth  of 'Sharks.    (Galeocerdo  arcticus.) 


CAINOZOIC 


221 


Fig.  189. 
FISH  OF  THE  MIOCENE. 


1.  Oaleocerdo  pristodontns.  2.  Galeocerdo  latidens.    3.  OxyrhinaDenorii.  4,  6, 7.  Lanma  elegani. 
5.  Ischyriia  antiqua.    8.  Oaleooerdo.    9.  Trygon.    10.  Pycnodont  tooth. 

19* 


222 


MANUAL  OP  GEOLOGY. 


Fig.  190. 
GASTEROPODA  OF  THE  MIOCENE. 


Pymla  reticulata. 


Cancellaria  reticulata. 


Fusui  exilis. 


CAINOZOIC  DIVISION. 


223 


Fig.  191. 
GASTEROPODS  OF  THE  MIOCENE. 


Murex  globosa.    (Half  natural  size.) 


Galeodia  Hodjjii. 


Murex  umbrifer. 


224 


MANUAL  OF  GEOLOGY. 


Fig.  192. 
GASTEEOPODS  OF  THE  MIOCENE. 


Terebra  unilineata.  VolutaTrenholmii. 


Fusus  equalis,  E. 


Pleurotoma  lunatum.  Voluta  oUuia. 


Cancellaria  Carolinensia. 


CAINOZOIC   DIVISION. 

Fig.  193. 
MIOCENE  FOSSILS. 


225 


1.  Fasciolaria  elegans.  2.  Fasciolaria  Sparrovi.  3.  Eulima  hevigata.  4.  Cerithium.  5.  Eulima 
eubulata.  6.  Cerithium  annulatum.  7.  Pyramidella  arenosa.  8.  Pleurotoraa  flexuosa.  9.  Pleurotoma 
tuberculata.  10.  Pleurotoma  limatula,  H.  Pleurotoma  elegana.  12.  Planorbis  bicarinata.  13.  Helix 
labyrinthica.  14.  Helix  tridentata. 


226 


MANUAL   OF   GEOLOGY. 

Fig.  194. 
MIOCENE  FOSSILS. 


1.  Oliva.  2.  Oliva  literata,  Say.  Conus  diluvianus.  4.  Conns  adversarius.  5.  Marginella  oliYfe- 
formis.  6.  Marginella  limatula.  7.  Marginella  constricta.  8.  Erato.  9.  Marginella  inflexa.  10. 
Marginella  elcvata.  11.  Marginella  ovata.  12.  Cyprea  Carolinensis.  13.  Mitra  Carolinensis.  14. 
Terebellum  coustrictum. 


CAINOZOIC   DIVISION. 


227 


Fig.  195. 
MIOCENE  FOSSILS. 


1! 


1.  Dentalium  attenuatum.  2.  Caecum  annulatum.  3.  Dentalium  thallus.  4.  Crepidula  forni- 
catum.  5.  Trochita  centralis.  6.  Crucibulum.  7-  Crueibulum  ramosum.  8.  Cmcibulum 
multilineatum.  9.  Crepidula  plana.  10.  Fissurella  redmicula.  11.  Petaloconchus  sculpturatus. 


223 


MANUAL   OF   GEOLOG5T. 


Fig.  196. 
MIOCENE  FOSSILS. 


Flicatula  marginata. 


CAINOZOIC   DIVISION. 

Fig.  197. 
MIOCENE  FOSSILS. 


229 


Pecten  Madisonius. 


Pecten  ehoreus. 


20 


230 


MANUAL  OF  GEOLOGY. 


Fig.  198. 
MIOCENE  FOSSILS. 


Axineae  suboTatns. 


Area  centenaria. 


C&rdita  arata. 


CAINOZOIC   DIVISION. 


231 


Fig.  199. 
MIOCENE  FOSSILS. 


1.  Mytilus   incrassatus.     2.  Gnathodon  Grayi.     3.   Horny  core  of  the  Jaw   of  a  Cephalopod 
(Eocene).    4.  Cardium  muricatum  ?    5.  Corbicula  densata.    6.  Valve  of  a  Cirripoda. 


232 


MANUAL   OF   GEOLOGY. 

Fig.  200. 
MIOCENE  FOSSILS. 


Lucina  Pennsylyanica. 


Venus  latilirata. 


CAINOZOIC   DIVISION. 


233 


Fig.  201. 
MIOCENE  FOSSILS. 


Venus  cribraria. 


20* 


Astarte  uadulata. 


234 


MANUAL   OF   GEOLOGY. 

Fig.  202. 
MIOCENE  FOSSILS. 


Glycimeris  reflexa. 


Glycimeris  abrupta. 


Solecurtis  caribxus. 


CAINOZOIC   DIVISION 


285 


Fig.  203. 
ECHINODERMATA  OF  THE  MIOCENE^ 


Rosette,  beneath. 


Gonioclypeus  subangulatus,  E. 


a,  6,  c.  Amphidetus  Virginianus  (Forbes). 


236 


MANUAL   OP   GEOLOGY. 


Fig.  204. 
CORALS  AND  BRYOZOA  OF  THE  MIOCENE. 


Lunulites  contigua. 


Liunulitcs   denticu- 
latus  (enlarged). 


CATNOZOIC    DIVISION. 


237 


Fig.  205. 


Tetralophodon,  or  Mastodon  of  the  Miocene.    (Half  natural  si*e.) 


238  MANUAL    OF   GEOLOGY. 

The  elephant  bones,  which  occur  in  New  York,  prove  that  it  was 
cotemporaneous  with  the  Mastodon  there;  but  the  elephant's 
remains  have  not  been  found  in  the  Miocene  marl. 

The  older  Miocene  of  White  River  has  furnished  remarkable 
animal  remains  which  have  been  described  and  finely  illustrated  by 
Prof.  Leidy.  Among  these  remains  ruminants  are  particularly 
worthy  of  note.  Several  genera  belong  to  those  which  were 
described  by  Cuvier,  but  which  belonged  to  the  Eocene,  viz.,  the 
Anoplotherium  and  the  Palseotheriuin  giganteum ;  the  latter  being 
twice  the  size  of  the  Palseotherium  magnum  of  the  Paris  basin. 
Two  species  of  Rhinoceros  and  several  species  of  Tortoises,  closely 
allied  to  the  genus  Emys,  are  not  uncommon.  The  Cetacean,  fig. 
187  (2),  is  a  remarkable  form  of  tooth  for  this  family — having  a 
resemblance  to  the  canine  of  the  Hippopotamus. 

189.  Pliocene. — In  this  period  the  ocean  had  become  divided 
into  bays,  estuaries,  and  gulfs,  to  about  the  same  extent  as  they  are 
at  the  present  time.  But  oscillations  of  the  surface  to  a  much 
greater  extent  took  place,  and  hence  the  frequent  changes  of  level 
make  it  very  difficult  to  recognise  the  formations  of  this  period. 
Careful  comparisons,  however,  of  the  species  of  mollusca  which 
marine  and  fresh-water  beds  contain  with  those  now  living  in  the 
vicinity  and  upon  the  coast,  will  furnish  the  best  data  by  which  the 
age  of  any  given  bed  may  be  determined.  The  group  of  fossils  of 
the  Pliocene,  when  compared  with  the  living  species,  amount  nume- 
rically to  between  40  and  95  per  cent.,  while  the  Miocene,  as  we 
have  seen,  only  amount  to  between  20  and  40  per  cent. 

The  Pliocene  is  older  than  the  drift,  and  no  doubt  extensive  beds 
belonging  to  this  era  have  been  entirely  washed  away,  and  proba- 
bly in  some,  perhaps  many  instances,  their  organic  contents  have 
been  lodged  in  boulder  clays,  or  drift  beds  composed  of  sand,  clay, 
and  calcareous  matter. 

lu  Europe  the  Sicilian  tertiaries,  the  crag  of  Norfolk,  and  sub- 
apennine  marls,  are  referred  to  the  Pliocene. 

In  this  country  they  are  always  quite  limited  in  extent,  similar 
to  isolated  oyster  banks ;  they  differ  considerably  in  mineral  charac- 
ter, and  in  color ;  some  are  beds  of  sand,  others  are  rich  in  lime, 
and  form  excellent  fertilizers.  In  South  Carolina  the  localities  at 
which  Pliocene  beds  occur,  are  the  mouth  of  Little  River,  near  the 
North  Carolina  boundary,  Timber  Landing,  on  Little  River,  Wac- 
camaw  River,  and  in  North  Carolina  Waccamaw  Lake,  though  this 


CAINOZOIC   DIVISION.  239 

is  doubtful.  Darlington  District  also  contains  numerous  localities. 
Goose  Creek,  also,  on  the  plantation  of  G.  H.  Smith,  Esq.* 

In  North  Carolina  the  Pliocene  beds  have  not  been  sufficiently 
examined.  Beds,  which  seem  to  lie  in  the  horizon  of  those  which 
are  regarded  as  Pliocene  in  South  Carolina,  are  rather  Miocene ; 
that  is,  they  contain  a  less  percentage  of  living  species  than  those 
of  South  Carolina. 

190.  TJie  Post- Pliocene. — Those  shelly  beds  which  contain  95 
per  cent,  of  living  species,  are  placed  under  this  head.  They  do 
not  differ  materially  from  the  preceding  in  their  mineral  character- 
istics. 

The  most  celebrated  localities  upon  the  Atlantic  coast  are  those 
of  Ashley  Ferry,  Goose  Creek,  Stono,  and  John's  Island,  in  South 
Carolina. 

These  beds  are  remarkable  for  the  number  of  mammalian  re- 
mains which  they  contain. 

Among  the  fossils  which  have  been  determined  are  the  follow- 
ing : — Horse ;  Hippotherium ;  Tapir ;  Beaver ;  Rabbit ;  Megathe- 
rium; Mylodon  Harlani;  Mastodon;  Megalonyx;  Glyptodon;  Cervus 
Virginiaua ;  Opossum ;  Peccary,  Hog ;  Bison,  and  Elk.  Of  these 
some  are  living  at  a  distance,  but  not  on  the  Atlantic  coast,  as  the 
Tapir,  Beaver,  Bison,  Elk,  &c. 

The  following  are  extinct : — Mastodon,  Megatherium,  Megalonyx, 
Glyptodon,  Mylodon,  Equus,  and  two  species  of  Hipparion. 

These  fossils  are  found  in  other  states,  and  have  been  obtained 
from  widely-separated  localities.  Whether  the  Ox,  Elk,  Bison, 
Peccary,  Hog,  and  Tapir  were  the  cotemporaries  of  the  Mastodon, 
Megatherium,  Mylodon,  and  Glyptodon  is  not  certainly  determined, 
but  is  rendered  highly  probable  by  the  manner  in  which  their 
remains  are  associated  together,  and  in  a  common  bed. 

It  should  be  observed  that  the  ratio  of  extinct  to  the  living 
mammals  is  very  large,  and  differs  materially  in  this  respect  from 
that  which  has  been  determined  with  respect  to  the  mollusks. 

Many  large  mammals,  now  extinct,  have  been  found  in  the 
Pliocene.  The  Mammoth,  an  extinct  elephant,  fig.  206.  Fig.  207, 
Tooth  of  the  elephant  found  in  Western  New  York. 


*  Prof.  Holmes  of  Charleston  has  very  carefully  investigated  these  beds,  and 
nas  given  many  interesting  communications  to  the  scientific  world  concerning 
them. 


240  MANUAL   OF   GEOLOGY. 

The  Megatherium,  whose  bones  have  been  found  in  caves  and 
recent  formations  in  the  South- Western  States,  fig.  208.  Another 
remarkable  mammal,  the  Castoroides  Ohioensis,  or  extinct  beaver 
of  an  enormous  size.  Fig.  209  is  an  outline  of  its  skull  found  in 
the  marsh  at  Montezuma,  New  York. 

The  Mastodon,  fig.  210,  is  the  most  common  of  the  large  ex- 
tinct quadrupeds,  skeletons  having  been  found  in  New  York  nearly 
perfect. 

The  Great  Irish  Elk,  fig.  211,  seems  to  have  been  a  cotemporary, 
but  its  remains  have  not  yet  been  found  in  this  country.  The 
Mastodon  began  its  career  in  the  Miocene  period,  as  teeth  of  the 
Tetralophodon  have  been  found  associated  with  true  Miocene 
fossils. 


Ear  Bone  of  a  Whale  (Miocene).    (Half  natural  sizs.j 


CAINOZOIC  DIVISION. 


24: 


MAMMALS  OF  THE  GLACIAL  OR  POST-GLACIAL  PERIOD. 
%ty.  206. 


Mammoth  or  Extinct  Elephant. 


Keferred,  together  with  the  succeeding  plates,  to  Post-glacial, 
their  remains  repose  in  heds  upon  the  Drift. 
21 


242 


MANUAL   OF   GEOLOGY. 


MAMMALS  OF  THE  GLACIAL  OR  POST-GLACIAL  PERIOD. 
Fig.  207. 


Tooth  of  the  Fossil  Elephant. 

fr 


Fig.  208. 


The  Megatherium. 


Elephant  bones  with  the  foregoing  tooth  werfr  found  in  Cortland 
Co.,  N.  Y. 


CAINOZOIC  DIVISION. 


243 


Fig.  209. 
MAMMALS  OF  THE  POST-GLACIAL  PERIOD. 


Casteroides  Ohioensis.    Extinct  Beaver.    One-third  Natural  Size. 


The  perfect  cranium  of  this  extinct  Beaver  was  found  in  the 
Montezuma  Marsh,  New  York. 


244 


MANUAL  OP  GEOLOGY. 


Fig.  210. 
MAMMALS  OP  THE  POST-GLACIAL  PERIOD. 


The  Mastodon. 


The  perfect  skeleton  of  the  Mastodon  was  found  six  miles  west 
of  Newberg,  New  York 


CAINOZOIC   DIVISION. 


245 


Fig.  211. 


The  Great  Irish  Elk. 


No  remains  of  this  Elk  have  been  found  in  this  country. 
Europe  they  are  found  in  the  peat  bogs. 
21* 


In 


CHAPTER  XX. 

GLACIAL   OR   DRIFT   PERIOD. 

191.  THE  phenomena  which  establish  this  period  are  based  upon 
two  separate  and  distinct  classes  of  facts.  The  first,  are  impressed 
lines  or  grooves  upon  the  rocks,  which  have  a  uniform  direction 
over  a  large  geographical  area,  and  hence  their  explanation  on  the 
ground  of  accident  becomes  unphilosophical.  The  second  fact  is 
the  existence  of  rounded  and  semi-rounded  rocks  far  from  their 
parent  beds,  fig.  212,  but  on  certain  lines  of  traverse,  which,  if  fol- 

Fig.  212. 


Boulder  Scratches. 


(246) 


GLACIAL  PERIOD.  247 

lowed  back  along  the  direction  of  the  impressed  lines  observed  upon 
rocks,  would  lead  to  their  original  beds.  Hence  it  follows  that  a 
force  has  moved  these  rocks  in  a  certain  direction,  and  the  first  fact 
stated  the  impressed  lines,  and  the  second  fact  the  rocks  distant 
from  the  beds,  to  which  they  must  once  have  been  attached,  are 
linked  together,  and  as  phenomena  are  due  to  one  cause.  The  moving 
rock  scored  or  impressed  the  rock  over  which  it  passed.  Several 
other  facts  should  be  stated  :  1.  The  line  of  movement  was  north- 
erly and  southerly,  north-east  and  south-west,  or  from  the  north- 
west to  the  south-east,  with  intermediate  lines  or  directions.  The 
reverse  directions  are  unknown  in  the  northern  hemisphere.  But 
in  certain  limited  spaces,  east  and  west,  impressed  lines  exist,  as 
we  stated  years  ago,  in  the  Cattskill  Mountains. 

We  recognise,  in  these  phenomena,  a  movement  and  a  transporta- 
tion of  materials  which  we  may  now  say  was  not  confined  to  rocks, 
but  extended  to  the  soils.  This  movement  was  much  more  power- 
ful towards  the  north,  and  its  extent  seems  not  to  have  passed  south 
beyond  the  40th  degree  of  latitude,  or  the  latitude  of  Baltimore. 

192.  The  drift  phenomena,  when  considered  as  a  period,  are  sub- 
divided into  three  subordinate  ones :  1.  A  period  of  submergence; 
2.  A  period  of  rest;  and,  3.  Of  emergence.  The  division  may 
appear  objectionable,  as  it  may  seem  to  assume  what  is  not  proved; 
and  it  is  probable  it  would  follow  as  an  inference  from  facts  when 
stated,  rather  than  to  precede  the  facts  from  which  the  inference 
legitimately  followed.  The  division,  however,  is  borne  out  by  facts 
which  may  be  observed  in  Northern  New  York  and  Canada.  They 
stand  connected  with  three  distinct  beds  of  deposits;  the  first 
consisting  of  rounded  rocks,  usually  called  boulders,  which  lie  in 
beds  upon  the  naked  rock,  and  in  immediate  contact  with  the 
scratched  surface  which  has  been  described.  The  transportation 
of  this  bed  of  rocks,  sand,  &c.,  we  connect  with  the  period  of  sub- 
mergence. 

Upon  these  beds  the  clays  of  Champlain  and  Albany  repose. 
This  bed  of  clay,  which  is  about  one  hundred  feet  thick,  is  a  ma- 
rine deposit,  formed  in  quiet  waters.  The  statement  is  sustained 
by  the  evenness  of  the  strata,  and  the  existence  therein  of  marine, 
or  estuary  fossils.  The  deposition,  then,  of  this  great  bed  of  clay, 
which  is  sandy  towards  the  top,  marks  the  second  period,  that  of 
rest. 

Upon  this  marine  clay  boulders  are  again  found  distributed  in 


248  MANUAL   OF   GEOLOGY. 

beds,  though  generally  isolated.  They  appear  like  the  drift  boulders, 
at  the  bottom  of  the  clay.  These  mark  the  existence  of  the  third 
period,  the  boulders  being  connected  with  the  upward  moyements 
of  the  land,  by  which  the  marine  deposit  described  was  elevated, 
and  reclaimed  from  the  waters  of  this  comparatively  ancient  sea. 
In  the  second  period,  during  which  the  bed  of  clay  and  sand  was 
being  formed,  boulders  were  occasionally  transported  from  some 
distant  point,  and  deposited  in  this  clay,  but  the  principal  accumu- 
lations were  at  the  beginning  and  close  of  the  epoch. 

193.  The  sequence  of  events  appears  to  be  well  determined — 
first,  the  confused  formation  made  up  of  travelled  rocks,  which  could 
not  have  been  thus  transported  without  a  movement  of  the  land, 
which,  from  what  followed,  proves  to  have  been  a  submergence ;  for 
we  find,  in  the  next  place,  the  marine  deposit,  which  must  have 
accumulated  under  a  considerable  depth  of  water.  In  the  third 
place,  the  land  is  lifted  to  its  present  level  by  an  upward  movement, 
which  was  effected  probably  by  a  rapid  movement,  which  caused  a 
speedy  drainage  by  currents  and  streams,  to  which  was  imparted 
a  competent  force  to  move  the  loose  rocks  of  the  surface.  The 
tendency  would  be  to  flow  in  the  direction  of  the  valleys;  and 
hence,  as  the  valleys  are  nearly  north  and  south  in  New  York  and 
Vermont,  the  loose  rocks  would  be  carried  in  those  channels. 

"We  pointed  out,  long  ago,  one  of  the  consequences  of  this  sub- 
mergence, viz.,  the  connection  by  water  of  the  Gulf  of  St.  Lawrence 
and  the  Bay  of  New  York.  This  is  sustained  by  the  existence  of 
the  remains  of  whales  in  the  clay,  in  the  valley  of  Lake  Champlain. 
An  arm  of  the  northern  sea,  extending  to  the  Bay  of  New  York, 
would  admit  of  northern  currents,  and  perhaps  lie  in  the  direction 
of  the  route  which  icebergs  would  travel.  New  England,  and  a 
part  of  New  York,  during  the  drift  period,  were  an  inland,  sepa- 
rated from  the  central  part  of  New  York  by  a  narrow  strait. 

Other  events  appear  to  be  connected  with  the  drift  period ;  the 
excavation  of  the  soft  rocks  in  the  form  of  basins,  which  are  now 
filled  with  fresh  water.  The  long  axes  of  the  inland  lakes  of  New 
York  are  directed  not  only  in  lines  nearly  parallel  with  each  other, 
but  also  in  the  direction  of  the  impressed  lines  upon  the  rocks.  Lakes 
are  no  doubt  due  to  diluvial  action,  as  it  is  often  called.  Lakes 
proper  scarcely  exist  in  Southern  States  beyond  the  limits  of  the 
drift. 

The  lakes  of  North  Carolina  originated  in  fires  which  have  con- 


GLACIAL  PERIOD. 


249 


eumed  the  peat  to  a  considerable  depth.  They  are  surrounded, 
and  indeed  based  upon  marine  sands  and  clays,  and  are  entirely  re- 
moved from  those  causes  which  scooped  out  those  lake  basins  in 
the  Northern  States. 

Fig.  213. 


1.  Mya  truncata.    2.  Tritonium  anglicum.    3.  Bhynconella  psittacea.    4.  Saxicava  rugosa. 

The  fossils  of  the  Drift  period  are  not  numerous.  In  England  the  following 
list  is  given  by  Phillips.: — Elephas  primigenius,  Hippopotamus  major,  Rhi- 
noceros tichorhinus,  Felis  spelsea,  Hysena  spelsea,  all  of  which  are  extinct; 
besides  which  there  are  the  bones  of  the  wolf,  horse,  ox,  and  Irish  elk.  In  New 
York  the  bones  of  the  elephant  are  found  in  drift,  and  the  bones  of  the  Mastodon 
are  found  above  the  drift.  The  remains  of  the  whale  in  the  Valley  of  Lake 
Champlain  belong  also  to  this  period.  In  the  sands  above  the  clay  more  than 
twenty  species  of  mollusks  have  been  obtained,  most  of  which  now  live  in  lati- 
tudes farther  north.  The  annexed  are  figures  of  some  of  the  most  common  fos- 
sils of  Lake  Champlain  and  Beaufort,  C.  E.,  which  belong  to  this  period. 

The  foregoing  division  of  the  deposits  which  are  closely  con- 
nected with  this  period,  may  be  admitted  without  adopting  the 
theory  that  these  changes  of  level  were  the  efficient  cause  of  the 
movements  of  boulders,  gravel,  soil,  &c.  The  facts  as  stated  rela- 
tive to  these  changes  of  level  must  be  admitted.  The  transporta- 
tion of  boulders  by  icebergs  is  another  fact,  the  movement  of 
glaciers  is  another,  both  of  which  are  independent  of  the  movements 
described. 

This  period  is  often  called  the  Glacial  period,  because  it  was 
attended  with  a  reduction  of  temperature,  which  seems  to  be  sup- 
ported by  the  occurrence  of  a  fauna  which  strictly  belongs  to  a 


250  MANUAL   OF   GEOLOGY. 

more  northern  region.  It  is  probable,  however,  that  the  reduction 
was  by  no  means  excessive ;  and  it  also  is  probable  the  occurrence 
may  be  accounted  for  by  the  presence  of  icebergs,  which  might, 
during  the  submergence  of  the  land  already  referred  to,  take  the 
open  channel  between  the  Gulf  of  St.  Lawrence  and  the  Bay  of 
New  York.  We  now  find  occasionally  boulders  in  the  clay  which 
appear  to  have  been  dropped  from  icebergs.  They  would  not,  how- 
ever, be  confined  to  this  channel,  but  become  stranded  along  the 
whole  length  of  the  then  existing  coast  line. 

194.  The  boulders,  which  belong  to  the  Drift  period,  or  Glacial 
epoch,  are  often  confined  to  distinct  belts  of  country.  Some  of 
these  belts  may  be  pointed  out.  They  are  distinguishable  from 
other  belts  by  the  predominance  of  certain  boulders  which  are  pecu- 
liar, and  whose  parent  rock  is  limited. 

Thus  the  Adirondacks  of  Northern  New  York  furnish  all  the 
Hypersthene  rock  which  lies  southward  of  this  cluster  of  moun- 
tains. The  most  distinct  belt,  or  train  of  boulders  from  these 
mountains,  passes  through  Amsterdam,  Montgomery  county,  New 
York.  This  village  is  upon  the  Erie  Canal,  thirty  miles  west  of 
Albany.  As  this  place  is  approached  from  the  east,  boulders  of 
Hypersthene  rock  begin  to  appear.  Near  the  village,  and  also  a 
short  distance  to  the  west  of  it,  they  become  abundant.  Going 
farther  west  they  diminish  in  numbers,  and  finally  disappear  en- 
tirely. The  belt  is  about  five  miles  wide.  Going  south,  they  will 
be  found  lying  upon  the  northern  slope  of  the  Helderberg,  over 
which  they  pass.  Upon  the  slope,  and  in  the  valleys  of  the  Catts- 
kill,  they  also  occur.  Some  reach  the  extreme  limits  of  Orange 
county.  From  Amsterdam  northerly  they  may  be  traced  to  the 
Adirondacks,  becoming  more  numerous  near  the  parent  beds ;  but 
to  the  north  of  them  no  boulders  of  this  rock  can  be  found.  An- 
other remarkable  instance  of  a  similar  rock,  which  has  travelled 
far,  lies  upon  the  eastern  shore  of  Lake  Ontario  and  the  St.  Law- 
rence. Hypersthene  boulders,  those  referred  to,  though  not  very 
numerous,  are  sometimes  met  with.  The  feldspar  of  these  boulders 
is  of  a  lighter  color,  or  has  a  bronze  tint,  instead  of  a  blue,  which 
is  the  most  common  tint  of  the  labradorite  of  the  Adirondacks.  It 
might  at  first  be  maintained  that  they  were  also  derived  from  the 
Adirondacks,  but  they  cannot  be  traced  in  that  direction.  To  the 
eastward  they  disappear  entirely,  and  hence,  in  order  to  find  the 
direction  from  which  they  came,  it  is  necessary  to  follow  the  train. 


GLACIAL  PERIOD.  251 

This  leads  in  the  direction  of  Labrador,  where  this  rock  is  known 
to  exist. 

The  calciferous  sand  rock  of  Lake  Champlain,  the  quartz  rock  at 
the  base  of  the  Taconic  system,  may  each  be  followed  more  than  a 
hundred  miles  in  a  north  and  south  direction. 

When  a  hard  rock  of  a  peculiar  kind  is  scattered  upon  the  sur- 
face, it  may  be  traced  to  the  source  from  which  it  was  derived.  The 
magnetic  iron  ores  occur  in  the  drift  in  Greenbush,  and  the  neigh- 
borhood of  Albany,  which  no  doubt  came  from  the  western  side  of 
Lake  Champlain. 

195.  From  the  foregoing  facts,  we  find  that  boulders  not  only 
lie  in  valleys,  but  they  have  been  carried  up  steep  declivities,  and 
over  mountains,  and  from  one  valley  to  another.  They  must  there- 
fore have  been  transported  by  agents  which  are  not  now  in  opera- 
tion. In  the  Northern  States  the  lines  or  grooves,  scored  upon  the 
rocks,  point  to  the  Arctic  regions.  There  are  no  mountains  which 
can  be  regarded  as  the  culminating  points  to  which  boulders  can 
be  traced,  and  from  which  they  have  radiated  in  different  direc- 
tions, which  would  have  been  the  case  had  they  been  carried  for- 
ward by  glaciers. 

The  Drift  period,  though  remote,  is  undoubtedly  the  last  which 
is  connected  with  the  great  changes  which  have  taken  place  upon 
the  earth's  surface.  The  materials  moved  rest  upon  all  the  general 
formations  which  have  as  yet  been  recognised.  Beds  of  recent 
origin,  the  alluvials,  &c.,  are  more  recent.  A  similar  period  of 
minor  importance  occurred  in  the  period  to  which  the  Trenton 
limestone  belongs.  On  splitting  off  a  mass  from  a  ledge  of  Tren- 
ton limestone,  the  mass  split  so  as  to  be  directly  on  a  scored  and 
grooved  surface,  the  piece  split  off  exhibited  the  relief  side,  and 
the  fixed  portion  of  the  rock  the  scored  surface.  This  mass  may 
be  examined  at  Plattsburg,  immediately  west  of  the  village  upon 
the  river's  bank.  Four  miles  north,  at  Cumberland  Head,  the  same 
stratum  can  be  recognised,  with  its  scored  surface,  as  at  the  village. 
The  striae  of  the  Trenton  epoch  run  east  and  west.  Probably 
similar  phenomena  may  be  observed  by  an  attentive  examination  of 
the  rocks  belonging  to  other  periods. 

The  contour  of  the  country,  during  the  epoch  of  the  drift,  was 
probably  much  the  same  as  now.  This  opinion  is  based  upon  the 
deflection  of  the  train  of  boulders  when  they  approached  a  range 
of  mountains.  The  current  bearing  along  boulders  towards  the 


252  MANUAL   OF   GEOLOGY. 

Cattskill  Mountains  was  deflected  near  the  base  to  the  eastward  j 
the  train,  in  part,  instead  of  passing  directly  over  the  highest  part, 
crossed  the  valley  of  the  Hudson,  and  we  find  boulders  of  the 
Oriskany  sandstone  on  the  east  side  of  the  river,  which  were  torn 
from  the  northern  slope  of  the  Helderberg.  Some  of  the  lower 
valleys  of  the  Cattskill  retain,  east  and  west,  lines  of  scoring  as 
distinct  as  those  at  the  base.  These  were,  no  doubt,  due  to  deflec- 
tion. , 

196.  The  force  which  carried  boulders  over  surfaces  so  uneven, 
and  up  steep  declivities,  must  have  been  immense.  Upon  the  north- 
west side  of  Stonehill,  in  Williamstown,  the  rock  of  which  is 
quartz,  superficial  indentations  may  be  seen  upon  some  of  the  cliffs, 
proving  that  the  surface  was  struck  with  great  force  by  moving 
rocks. 

The  Drift  period  was  considerably  protracted.  We  infer  this 
from  the  changes  which  the  surface  underwent  during  its  continu- 
ance. Rocks,  for  example,  were  deeply  scooped  out,  and  vast 
masses  removed  by  denudation.  In  Williamstown  about  1600  feet 
of  Oakhill  was  worn  down  and  removed,  leaving  still  an  elevation 
of  1700  feet.  The  whole  of  the  slates  and  limestone,  equivalent 
to  those  of  Graylock,  a  few  miles  south,  down  to  the  quartz  rock, 
were  removed  by  denudation.  Graylock  is  3600  feet  above  the 
level  of  the  sea,  and  the  quartz  rock,  at  its  base,  is  about  700  feet. 
All  above  the  quartz,  then,  of  Oakhill  has  been  removed,  as  this 
is  its  top  rock. 

We  have  then  sufficient  evidence  that  violence  and  great  commo- 
tion belonged  to  the  Drift  era,  and  that  it  was  not  a  transient  one, 
but  occupied  a  period  of  considerable  duration,  during  which  large 
portions  of  important  formations  were  actually  worn  away,  and 
transported  to  distant  points.  The  hard  rocks,  those  which  were 
capable  of  resisting  violent  shocks,  lie  still  along  the  path  over  which 
the  formation  travelled,  telling  us  not  only  the  fact  of  its  removal, 
but  also  much  relative  to  the  force  employed  and  the  quantity  of 
material  acted  upon.  These  materials  are  deposited  in  valleys,  upon 
the  slopes  of  mountains,  and  indeed  they  constitute  the  great  part 
of  New  England  and  New  York  soils,  wherever  they  may  lie. 

197.  In  conclusion,  we  remark,  that  it  is  no  discredit  to  the 
geologist  to  acknowledge  his  inability  to  offer  a  satisfactory  expla- 
nation of  all  the  phenomena  we  have  spoken  of.  We  believe  that 
the  glacial  theory  of  Agassiz  explains  fully  a  certain  class  of  phe- 


GLACIAL  PERIOD. 


253 


nomena,  and  that  the  iceberg  theory  of  Sir  Charles  Lyell  must  be 
received  in  explanation  of  many  other  facts  which  stand  in  intimate 
relation  to  this  subject.  We  believe,  however,  that  the  soil  in  a  body 
has  been  moved,  with  its  boulders  intermixed,  and  hence,  in  order 
to  account  for  a  general  movement  of  loose  materials,  we  believe  it 
necessary  the  land  should  rapidly  subside,  by  which  the  barriers  of 
a  great  northern  sea  would  be  removed.  A  rush  of  waters  would 
follow  sufficient  to  force  along  not  only  the  loose  matters,  but  break 
up  the  fixed  rocks.  The  Erie  Canal,  in  some  of  its  worst  breaks, 
has  torn  up  the  fixed  beds  of  slate  and  limestone  upon  its  borders. 
But  the  force  of  the  waters  of  the  Erie  Canal,  when  unrestrained 
by  its  banks,  is  nothing  in  comparison  to  a  deluge  of  oceanic  waters 
unrestrained  by  shores. 

We  have  spoken  of  the  passage  of  boulders  up  the  face  of  steep 
slopes,  and  the  existence  of  striae  indicating  such  a  movement  upon 
the  western  face  of  the  Taconic  range  in  Petersburg,  N.  Y.  These 
scratches  or  strise  may  be  explained  on  the  ground  that  ancient  gla- 
ciers once  existed  upon  the  peaks  of  this  range ;  and  what  is  con- 
firmatory of  this  view  is  the  existence  also  of  ridges  of  sand  and 
pebbles  in  some  of  the  valleys  which  possess  the  character  of 
moraines  in  a  marked  degree. 


Boulder*. 


22 


CHAPTER  XXI. 

POST-GLACIAL     BEDS  —  ALLUVIUM  —  EOLIAN     SANDS  —  BOTTOM 

PRAIRIE — BLUFF  AND  RIVER    TERRACES COAST    SEDIMENTS — 

CAVERN    DEPOSITS  —  TRAVERTIN CORAL    REEFS VOLCANIC 

PRODUCTIONS. 

198.  POST-GLACIAL  beds  embrace  a  heterogeneous  series  of  de- 
posits, which  are  still  more  local  than  those  which  are  classed  under 
the  Cainozoic  division.     They  embrace  the  Quaternary  deposits  of 
many  geologists.     Under  either  name  they  include  the  Alluvium, 
Eolian  sand,  coast  and  deep  sea  sediments,  cavern  deposits,  bog 
or  peat,  travertin,  coral  reefs,  and  volcanic  productions,  Bottom 
prairie  and  Bluff  formation  of  the  West. 

The  Glacial  formation  is  excluded,  on  the  ground  that  it  is  quite 
peculiar  and  distinct  in  itself,  and  occupies  a  definite  though  unde- 
termined period,  and  moreover  preceded  the  post-glacial  beds.  The 
latter,  excepting  the  Bottom  prairie  and  Bluff  formation  of  Professor 
Swallow,  are  products  of  the  present.  Certain  cavern  deposits  and 
travertin  are  no  doubt  older  than  the  Glacial  epoch,  but  those 
included  in  this  division  may  be  distinguished  from  the  pre-glacial; 
ty  their  organic  contents,  if  they  have  any. 

199.  Alluvium,  or  washed  strata,   are  accumulations  of  sand, 
gravel,  and  earth  upon  the  banks,  and  at  the  mouths  of  rivers. 
They  are  quite  limited,  excepting  upon  such  broad  rivers  as  the 
Mississippi.     They  contain  leaves  and  trunks  of  trees  of  our  time, 
and  bones  of  the  living  vertebrates,  and  mollusks  of  the  stream 
which  has  deposited  the  bed.    Alluvium  may  be  distinguished  from 
other  deposits  by  the  relation  which  it  holds  to  the  agent  which 
deposits  it. 

200.  Eolian  Sands. — They  are  coast  sands,  which  are  continu- 
ally driven  inwards  by  the  prevalent  winds  upon  the  coast.     The 
sands  are  first  brought  forward  by  breakers,  or  strong  waves,  and 
carried  up  beyond  the  reach  of  subsequent  waves,  partly  by  the  aid 
of  wind.    The  Kill-Devil  Hills,  near  Nag's  Head,  and  all  the  sand- 
banks along  the  coast  of  North  Carolina,  are  Eolian. 

(254) 


POST-GLACIAL  PERIOD.  255 

When  the  lighter  implements  of  iron,  as  spears  and  fishing  tools, 
coins,  &c.,  are  lost  in  the  midst  of  the  shore  waves,  they  are  cast 
ashore  in  a  few  days.  The  winds,  however,  drive  the  sand  for  miles 
inland,  and  frequently  pile  it  in  banks,  intermixed  with  shells, 
which  are  also  carried  inland  during  strong  gales. 

201.  Bottom  Prairie,  Lagoon,  and  Lake  Deposits. — In  the  great 
valleys  of  the  West  there  is  an  extensive  formation,  which  has  been 
called  by  Professor  Swallow  Bottom  Prairie.     It  was  formed  by 
agencies  which  have  ceased  to  operate.     Perhaps  it  was  deposited 
from  lagoons  when  the  course  of  those  large  western  rivers  was 
obstructed.  Bottom  prairies  are  composed  of  sand  clays  and  vegeta- 
ble mould,  all  of  which  are  arranged  in  strata.     They  constitute 
the  rich  bottom  lands  of  this  region.     The  action  of  the  present 
rivers  is  to  wear  away  these  bottoms,  and  form  therefrom  the  allu- 
vial bottoms. 

202.  Bluff  and  River  Terraces. — This  formation  is  geographically 
higher,  and  occupies  ridges  and  river  bluffs,  but  it  descends,  and 
sinks  beneath  the  prairie  bottoms.     The  material  is  silicious,  stained 
with  iron,  and  is  also  marly.    Its  stratification  is  irregular.    It  rests 
on  the  glacial  accumulations. 

In  the  West  this  formation  is  quite  extensive.  "  It  caps/'  ac- 
cording to  Professor  Swallow,  "  all  the  bluffs  of  the  Missouri,  from 
Council  Bluffs  to  its  mouth,  and  those  of  the  Mississippi  from  the 
mouth  of  the  Des  Moines  river  to  that  of  the  Ohio."  Other  au- 
thors notice  this  formation  as  existing  upon  the  Wabash,  Ohio,  and 
Red  river. 

The  foregoing  formation,  post-glacial,  frequently  contains  organic 
remains  in  great  abundance.  They  do  not  differ  from  the  living 
fauna  except  in  the  Vertebrates,  and  it  is  not  easy  to  determine 
whetner  in  these  instances  they  were  not  derived  from  older  beds. 
The  mollusks,  both  terrestrial  and  fluviatile,  belong  to  existing 
genera  and  species ;  and  yet  there  are,  no  doubt,  many  beds  which 
have  been  deposited  since  the  Grlacial  epoch,  which  are  really  very 
old. 

This  formation  is  regarded  as  lacustrian  by  Professor  Swallow, 
who  maintains  that  the  sites  of  the  great  valleys  of  the  Mississippi 
and  Missouri  contained  large  lakes,  receiving  rivers  and  smaller 
streams. 

The  river  valleys  of  New  York  and  New  England  have  pre- 
served terraces,  which  frequently  assume  the  form  of  bluffs,  which 


256  MANUAL   OF   GEOLOGY. 

probably  date  back  to  the  period  of  the  bluff  formation  of  the 
Western  river  valleys.  Their  origin  in  New  England  may  have 
been  connected  with  an  early  condition  of  the  river  courses.  Ob- 
struction of  their  courses  by  barriers,  causing  expansions  into  lakes, 
which  may  have  been  connected  with  a  change  of  level  of  the  coun- 
try, and  the  wearing  down  of  obstructions,  and  may  also,  in  the 
course  of  time,  have  formed  the  succession  of  terraces  which  skirt 
the  valleys.  The  terraces  are  not  perfect,  and  similar  on  both  sides 
of  the  river,  at  the  opposite  points,  but  rather  alternations  of  them 
from  one  to  the  other  side. 

In  the  Southern  States  old  river  bottoms  are  easily  recognised  by 
beds  of  gravel  and  rounded  stones  of  a  suitable  size  for  pavements. 
These  bottoms  are  fifty  feet,  sometimes  more,  above  the  present 
beds  of  the  rivers.  They  exist  even  near  their  sources.  We  find 
beds  of  this  description  far  in  the  interior  of  North  Carolina,  at 
Morganton,  and  Eastern  Tennessee,  and  at  many  places  west  of 
the  Alleghanies. 

203.  Coast  Sediments  and  Sediments  of  Deep  Soundings. — The 
materials  which  are  brought  to  the  ocean,  or  its  bays  and  sounds, 
are  continually  receiving  accessions  of  mud,  sand,  and  gravel,  land 
plants  and  terrestrial  animals.     So  also  the  shore  and  the  deep  sea 
are  continually  receiving  the  sediments  brought  down  by  all  the 
large  rivers.     This  matter  is  in  one  sense  sifted  and  assorted.     The 
calcareous  matter  is  carried  out  to  sea,  and  is  destined  to  build  or 
raise  the  bottom  of  the  deep  sea,  while  the  sand  is  deposited  along 
the  coast,  or  in  shallow  water. 

204.  Cavern  Deposits. — In  all  caverns  and  caves  water  perco- 
lates through  the  roof,  and  carries  along  matters  which  it  has  dis- 
solved.    A  part  of  this  is  retained,  or  adheres  to  the  roof  and  wall, 
and  if  pendent,  is  called  stalactite;  that  portion  deposited  upon  the 
floor  is  stalagmite.     The  process  goes  on  continually.     Bones  of 
bats,  mice,  and  frequently  the  larger  quadrupeds,  are  encased  in 
stalagmite,  or  mud,  which  is  brought  in  by  streams. 

The  most  ancient  caverns  date  back  to  a  period  before  the  Gla- 
3ial  epoch,  and  contain  bones  of  extinct  quadrupeds. 

205.  Travertin,  or  Tufa. — Springs  which  issue  from  and  flow 
over  calcareous  rocks,  dissolve  lime,  provided  the  water  holds  in 
solution  carbonic  acid.    When  these  waters  reach  the  air,  a  part  of 
the  carbonic  acid  escapes,  and  lime  is  deposited  in  a  bank.     It  is  a 
porous  mass,  in  which  leaves,  sticks,  and  logs  are  enveloped,  and 


CAINOZOIC   DIVISION. 


257 


which  are  often  petrified.  Sometimes  bog  ores,  mixed  with  man- 
ganese, are  deposited,  like  travertin.  Many  such  springs  have  dried 
up,  or  cease  to  flow ;  but  the  bog  ore  or  ochre  remains,  adhering 
to  stones,  forming  a  ferruginous  conglomerate. 

206.  Coral  Reefs,  Shell  Beds,  &c. — In  warm  latitudes  polyps 
are  busily  engaged  in  building  up  their  curious  calcareous  habita- 
tions.    The  coast  of  Australia,  the  islands  of  the  Pacific,  and  the 
Bermudas  furnish  examples  of  coral  reefs  on  a  large  scale.     Coral 
reefs  begin  to  be  formed  upon  sunken  islands,  around  sunken  vol- 
canic cones,  and  along  coasts  where  the  water  is  30  or  40  fathoms 
deep.     The  coral  rises  to  the  surface,  when  it  is  broken  by  winds, 
and  heaped  up,  and  additions  are  made  to  the  rising  ridge  from 
various  quarters,  as  dead  shells,  till  finally  the  ridges  rise  above 
high  water,  when  they  are  resorted  to  by  birds.     Seeds  germinate, 
trees  and  shrubs  grow,  and  an  island  is  seen  to  have  risen  from  the 
depths  of  mid-ocean. 

The  coral  reefs  of  Bermuda  consist  partly  of  a  chalky  mass 
made  up  of  comminuted  corals  and  shells.  Where  coral  cliffs  are 
found,  or  banks  which  rise  considerably  above  the  level  of  the  sea, 
as  in  the  West  Indies ;  they  are  ascribed  to  volcanic  action. 

Where  corals  begin  to  build  their  habitation  upon  sunken  peaks, 
they  rise  to  the  surface  in  a  circular  form,  and  enclose  within  a  salt 
lake;  such  an  arrangement  of  coral  is  called  an  Atoll.  The  process 
of  building  goes  on  while  the  land  below  is  still  slowly  sinking,  as 
is  proved  by  the  existence  of  dead  coral,  at  a  depth  of  1500  or 
more  feet,  a  depth  which  is  incompatible  with  the  existence  of  this 
class  of  animals. 

207.  Volcanic  Productions. — Modern  lava  and  ashes,  mud,  &c., 
thrown  out  within  the  historic  era,  belong  to  this  order  of  deposits. 


22* 


Atoll,  with  its  fringe  of  cocoanot  treea  and  lagoon  within. 


258 


MANUAL  OF   GEOLOGY. 


EXTINCT  MAMMALS  OF  THE  SLOTH  AND  ARMADILLO  TRIBES. 
Fig.  214. 


Mylodon  rolmstus. 


Fig.  215. 


Glyptodon  clavipes. 


CHAPTER  XXII. 


VOLCANOES,  VOLCANIC  ACTION,  AND  EARTHQUAKES. 

208.  THE  principles  which  have  been  stated  in  the  preceding 
chapters  respecting  the  forces  and  agencies  which  are  seated  in  the 
earth's  crust,  have  prepared  the  way  for  what  remains  to  be  said 
relative  to  Yolcanoes  and  Earthquakes. 

Volcano  is  a  word  which  is  applied  to  a  mountain  or  tract  of 
country  from  which  outbursts  of  fire,  molten  rocks,  ashes,  vapors, 
&c.,  take  place  from  the  interior  of  the  earth.  It  usually  occupies 
elevated  points,  and  hence  has  arisen  the  term  Volcanic  Mountains. 
But  they  appear  also  in  depressed  areas,  and  even  beneath  the  sea, 
when  they  are  called  submarine. 

The  form  which  the  summits  of  a  volcanic  mountain  assume  are 
conical,  or  that  of  a  cone,  which  arises  from  the  accumulation  of 
ejected  matters  from  the  vent,  fig.  216.  The  cone  itself  is  com- 


iff.  216. 


Volcanic  Cones. 

posed  of  ashes  and  stones,  which  fall  around  the  vent  during  its 
active  stage.  The  molten  rock,  which  also  issues  from  the  same 
vent,  or  from  the  mountain's  side  below,  flows  away  like  a  river  of 
fire,  and  when  cooled  remains  a  stream  of  black  porous  slag. 
Ejections,  however,  are  not  always  molten  and  fiery ;  mud  is  some- 
times ejected.  Volcanoes  are  irregular  in  their  action;  there  are 
periods  of  repose  and  of  activity,  and  the  intervals  between  them 
are  of  different  lengths.  The  symptoms  whiclnprecede  an  outburst 
are  not  numerous,  but  there  are  usually  rumbling  sounds  beneath, 

(259) 


260  MANUAL   OP   GEOLOGY. 

and  frequently  there  is  a  perfect  calm  and  quietude  of  the  atmo- 
sphere. The  outburst  of  a  volcano  is  accompanied  by  the  emission 
of  flame,  vapors,  explosions,  violent  expulsion  of  ashes  and  stones, 
some  of  which  are  projected  to  great  distances.  The  cloud  of  ashes 
is  often  sufficient  to  darken  the  atmosphere  for  fifty  miles  around, 
and  even  at  times  to  cause  the  darkness  of  night.  The  force  of 
volcanic  action  is  immense.  In  one  instance,  in  South  America,  a 
rock  weighing  200  tons  was  projected  nine  miles.  The  force  ia 
still  more  strongly  shown  in  the  elevation  of  a  column  of  lava  seve- 
ral thousand  feet  through  the  funnel  of  the  volcano,  or  in  the 
elevation  of  large  tracts  of  land.  Thus  in  Mexico,  three  or  four 
square  miles  in  extent  were  raised  550  feet,  from  which  height 
there  were  raised  numerous  conical  hills,  of  300  or  400  feet  toge- 
ther, with  the  mountain  JorullOj  1600  feet  high. 

209.  A  volcanic  mountain  may  be  regarded  somewhat  in  the 
light  of  an  arch,  which  has  been  raised  upwards  by  the  expansion 
of  vapors  and  gases,  beneath  which  it  is  often  excavated,  furnish- 
ing room  thereby  for  the  accumulation  of  steam,  vapor,  or  elastic 
gases ;  and  as  they  are  arranged  in  lines,  and  as  they  seem  fre- 
quently to  have  open  passages  of  communication,  a  volcanic  range, 
as  the  Andes,  for  example,  may  be  quite  hollow  beneath  through- 
out their  whole  extent.  The  loss  of  subterranean  substance,  during 
a  single  operation,  is  frequently  immense,  as  was  the  case  in  Iceland 
during  the  activity  of  Hecla,  in  1783 ;  when  a  molten  stream  of 
rock  flowed  down  its  sides  for  forty-two  days,  which  travelled  fifty 
miles,  and  then  branched  into  two  streams,  one  of  which  was  forty 
and  the  other  fifty  miles  in  length.  These  streams  varied  in  depth 
and  width,  according  to  the  face  of  the  country,  ranging,  however, 
from  600  to  1000  feet  in  depth.  Its  greatest  breadth  was  fifteen 
miles. 

A  South  American  chain  of  volcanic  vents  runs  east  and  west, 
beginning  with  the  Tuxtula,  on  the  Mexican  Gulf;  it  runs  west  to 
the  snowy  peaks  of  Orizaba  and  Popocatapetl ;  farther  west  still 
lie  the  volcanoes  of  Jorullo. 

The  volcanoes  of  Java  and  Sumatra  lie  in  a  line  parallel  with  the 
principal  axes  of  these  islands.  The  former,  instead  of  lava,  pours 
forth  during  its  eruptions  vast  quantities  of  mud  and  ashes ;  the 
mud  is  supposed  to  originate  from  the  materials  within  the  moun- 
tains themselves,  inconsequence  of  the  action  of  the  hot  acidulated 
waters  and  acid  sulphureous  vapors  generated  in  the  bowels  of  the 


VOLCANOES,  ETC.  261 

mountains.  These  vapors  destroy  or  reduce  to  a  pulp  all  rocks  witt 
which  they  come  in  contact. 

The  vertical  section  of  a  volcanic  mountain  shows  that  its  rock* 
have  been  rent  by  fissures.  These  run  in  different  directions,  and 
intersect  each  other.  These  fissures  have  been  filled  with  molten 
matter,  and  hence  the  appearance  resembles  a  net-work  of  dykes 

Volcanic  action,  in  the  main,  is  due  to  the  residual  heat  of  the 
interior  of  the  earth.  Hence  the  force  is  deeply  seated,  or  is  known 
to  issue  from  below  the  granites.  No  doubt  the  fires  are  seated 
among  those  materials  which  have  never  cooled.  A  theory  which 
is  based  on  any  other  foundation  would  not  explain  the  immensity 
of  volcanic  operations. 

210.  It  is  only  in  the  Cainozoic  era  that  the  common  phenomena 
of  volcanic  action  can  be  recognised.     Neither  cones  nor  lava  pro- 
per have  been  found  among  Palaeozoic  rocks.     They  are  traversed, 
however,  by  igneous  masses,  and  one  of  the  most  extensive  trap 
or  green-stone  formations,  a  submarine  ejection,  was  poured  forth 
near  the  close  of  the  Triassic  era. 

Volcanic  action  is  not  accompanied  with  the  same  phenomena  at 
different  times,  neither  do  different  volcanoes  eject  the  same  kind 
of  materials  during  different  eruptions.  At  one  time  it  is  a  thick 
heavy  lava,  which  flows  from  one  or  two  sides  of  the  crater.  The 
volcanoes  of  the  Sandwich  Islands,  according  to  Professor  Dana, 
are  boiling  pools  of  melted  rock ;  excavations,  rather  than  craters, 
and  their  activity  is  accompanied  with  moderately  loud  explosions, 
and  the  shrill  hissing  of  steam  issuing  from  a  boiler. 

211.  The  moon's  surface,  when  seen  through  a  good  telescope, 
appears  to  be  studded  with  volcanic  mountains ;  so  distinct,  indeed, 
are  its  craters  that  their  interiors  are  clearly  revealed.     In  all 
respects  the  lunar  volcanoes  resemble  outwardly  the  terrestrial  ones, 
only  it  presents  them  in  forms  and  numbers  which  greatly  exceed 
those  which  now  exist  upon  its  surface. 

212.  Earthquakes. — A  phenomenon  which  stands  in  direct  con- 
nection with  volcanic  action  is  the  earthquake.     It  consists,  essen- 
tially, of  movements  of  the  earth's  surface  in  the  form  of  waves, 
or  undulations,  which  travel  with  great  rapidity  in  all  directions 
from  the  focus  of  disturbance.     These  waves  are  due,  no  doubt,  to 
a  shock  arising  from  the  explosion  of  elastic  bodies  pent  up  in  cavi- 
ties, and  analogous  to  the  explosions  in  coal  mines,  only  immensely 
more  powerful.     They  precede  and  perhaps  continue  during  the 


262  MANUAL  OF   GEOLOGY. 

first  outbursts  of  volcanic  forces.  The  intensity  of  this  move- 
ment, or  force  of  the  shocks  communicated  to  the  strata,  is  supposed 
to  be  in  some  way  dependent  upon  the  diameter  of  the  vent  through 
which  the  gases  and  melted  matter  finally  escape.  The  throat  or 
chimney  through  which  the  volatile  matters,  lava,  &c.,  escape  from 
Vesuvius,  Etna,  and  the  South  American  volcanoes,  is  narrow  or 
constricted,  at  the  same  time  the  arch  above  the  subterranean  cavi- 
ties is  thickened  and  strengthened  by  immensely  heavy  deposits  of 
lava,  &c.  Hence,  under  these  circumstances,  volcanic  forces  are 
confined  by  strong  walls ;  and  hence,  when  the  forces  have  acquired 
strength  sufficient  to  rend  asunder  these  walls,  or  force  the  safety- 
valve,  it  will  be  attended  with  tremendous  earthquake  shocks.  On 
the  other  hand,  where  there  is  a  wide  opening  for  the  escape  of 
the  highly  heated  matters,  as  in  the  volcanoes  of  the  Sandwich 
Islands,  where  the  craters  are  rather  wide,  and  similar  to  excava- 
tions, volcanic  action  begins  and  goes  on  without  such  violent 
shocks  as  to  endanger  the  surrounding  country.  The  shock  of  the 
explosions  communicates  to  the  crust  an  impulse  which  generates  a 
wave,  which  usually  moves  onward  and  outward  with  great  velocity. 
The  surface  rises  and  falls  like  the  waves  of  the  sea;  or,  in  other 
words,  the  undulations  travel  onward  with  great  speed,  in  obedience 
to  the  ordinary  law  of  a  force  propagated  through  a  resisting 
medium. 

The  undulation,  however,  is  modified  by  the  position  and  condi- 
tion of  the  resisting  medium.  In  its  progress,  a  direct  undulation 
may  be  converted  into  a  gyratory  one,  by  an  increased  resistance  in 
its  course,  or  into  a  vertical  one,  at  the  place  situated  immediately 
above  the  point  of  impulse.  Considering  earthquakes  as  earth- 
waves,  it  is  evident  that  when  those  waves  are  generated  in  the 
ground  beneath  the  ocean,  their  impulse  must  be  communicated  to 
the  water  above,  whose  motion  will  partake  of  the  same  character. 
Waves  will  therefore  be  generated  therein,  which  will  travel  on- 
ward in  the  direction  which  the  impulse  communicates  ;  but  from 
the  nature  of  the  medium  the  water-wave  will  travel  with  less 
speed  than  the  earth-wave.  In  consequence  of  this  fact,  a  person 
upon  the  shore  where  two  waves  are  tending,  will  perceive  first  the 
earth-wave,  and  soon  after  the  water-wave  will  follow;  lastly, 
another  wave  will  be  recognised  through  the  medium  of  the  air. 
In  each  of  these  cases  the  rate  of  transit  depends  on  the  nature  of 
the  medium  which  receives  the  shock. 


263 

213.  The  effects  upon  the  earth's  crust  are  worthy  of  particular 
notice,  especially  with  reference  to  the  change  of  level  which  it 
undergoes  during  an  earthquake  paroxysm.     The  coast  of  Chili, 
for  example,  during  an  earthquake  in  1822,  was  permanently  ele- 
vated for  one  hundred  miles ;  in  some  places  more,  and  in  others 
less  than  ten  feet. 

214.  In  concluding  this  branch  of  the  subject,  we  remark  that 
the  student  will  sooner  or  later  perceive  that  geological  history 
necessarily  embraces  two  great  fields  of  investigation :  1.  Physical 
Geology,  including  the  dynamics  and  statics  of  geology;  and,  2. 
The  history  of  the  development  of  the  organic  kingdoms,  including 
palaeontology,  or  the  description  of  the  vegetables  and  animals  be- 
longing to  the  strata.    Each  furnishes  distinct  fields  of  research,  but 
the  highest  generalizations  grow  out  of  the  mutual  relations  disco- 
vered between  the  physical  movements  and  vital  forces  in  activity 
during  the  geologic  periods.     The  influence  of  the  physical  forces 
or  the  crust  movements  upon  the  organic  kingdoms,  has  ever  been 
exhibited  in  a  strong  light,  and  they  seem  to  stand  in  the  relation 
of  cause  and  effect.    But  however  this  may  be,  we  see  in  the  great 
series  of  movements  the  constant  operation  of  natural  causes  in 
opposition  to  miraculous  ones,  in  which  respect  the  phenomena  of 
the  physical  world  stand  in  contrast  with  the  organic  world;  for 
in  the  latter  we  have  necessarily  to  recognise  the  constant  interfer- 
ence of  a  miraculous  power  in  the  creation  of  new  organisms,  to 
replace  those  which  have  become  extinct.     The  process  of  extinc- 
tion, it  is  true,  may  be  in  obedience  to  a  natural  law ;  but  there  is 
in  operation  .no  law  by  which  life  force  is  imparted  to  matter,  ex- 
cept through  the  special  and  direct  will  of  the  Creator.     There  is 
no  spontaneous  evolution  of  life-forms  from  matter,  but  all  life-forms, 
through  all  the  vast  geologic  periods,  must  be  attributed  to  the  act 
of  one  Will,  in  whom  only  life  can  emanate. 

It  will  strike  any  one,  especially  the  palaeontologist,  that 
organic  forms  are  constantly  varying.  Each  system  has  its  own 
fauna,  each  has  its  own  history,  though  it  is  not  independent.  But 
he  will  be  particularly  struck  with  the  contrast  which  the  Palaeozoic 
world  furnishes  when  compared  with  the  Cainozoio;  and  this  con- 
trast will  place  in  its  true  light,  the  progress  the  world  has  made 
in  passing  from  a  Palaeozoic  to  a  Cainozoic  age. 


CHAPTER  XXIII. 


MINERAL   VEINS — VEINS   OF   ROCK   OR   EARTHY   MATTER. 


215.  A  VEIN  is  a  sheet  of 
mineral  matter  traversing  a 
rock,  or  series  of  rocks,  more 
or  less  obliquely,  and  some- 
times nearly,  if  not  quite,  par- 
allel for  short  distances,  at 
least,  with  their  component 
lamina  or  strata.  The  relation 
of  these  sheets  to  the  rock 
which  they  traverse  proves 
that  they  were  formed  after 
the  latter  was  consolidated. 

In  accounting,  therefore, 
for  their  formation,  it  is 
necessary  to  recur  to  the 
former  high  temperature  of 
the  earth,  and  to  employ  that 
well  known  elementary  fact, 
the  contraction  of  matter 
during  cooling,  in  order  to 
explain  the  origin  of  fissures 
in  its  crust.  The  matter  in 
a  vein  differs  from  that  of 
the  adjacent  rock,  and  the 
boundaries  are  usually  so 
distinct,  that  the  mass  of 
the  sheet  may  be  separated 
from  it,  though  in  some 
cases  the  cohesion  is  so  great 
that  in  the  attempt  the  ad- 
jacent rock  is  also  broken 
away.  The  rock  in  contact 
with  the  sheet  of  the  vein  is 
called  the  wall.  The  vein 


Fig.  217.   , 


Lead  Veiix  of  Rossic,  N.  Y. 


(264) 


MINERAL   VEINS,    ETC.  265 

is,  therefore,  bounded  by  two  walls :  the  foot  wall  below,  the  hanging 
wall  above.  The  obliquity  of  the  sheet  varies  from  verticality  to  a 
nearly  horizontal  position,  for  a  limited  space.  A  vein  is  often  quite 
flat  at  its  outcropping;  in  its  descent  it  becomes  more  vertical,  a  fact 
which  seems  to  affect  its  richness,  inasmuch  as  steep  veins  are  more 
loaded  with  metal  than  flat  ones. 

We  have  represented  a  vein  as  a  sheet  of  mineral  matter;  it 
should  be  stated  that  it  is  not  like  a  sheet — equal  in  thickness 
throughout — but  quite  variable  in  this  respect,  bulging  out  in  some 
places  and  contracting  in  others. 

216.  A  vein,  again,  is  composed   of  the  vein  stone   and   the 
metal  intermixed  with  it,  lying  in  favorable  veins  somewhat  in  sub- 
ordinate sheets  parallel  with  the  walls ;  in  other  cases  it  is  scattered 
through  the  gangue  or  vein  stone  somewhat  irregularly.     In  the 
most  favorable  veins  the  metal  lies  upon  the  foot  wall. 

217.  The  kind  of  gangue  or  stony  matter  associated  with  the 
metals  of  a  vein  is  generally  quartz  in  the  auriferous  and  copper 
veins  of  North  Carolina — these  veins,  however,  sometimes  contain 
calcspar.     But  numerous  minerals  occur  as  vein  stones,  as  sulphate 
of  barytes,  and  sometimes  strontian,  as  at  Rossic,  N.  Y.,  fluorspar, 
carbonate  of  iron,  associated  with  quartz,  as  at  several  copper  mines 
in  North  Carolina,  and  sometimes  epidote. 

The  direction  which  the  veins  of  this  country  pursue  is  northerly 
and  southerly,  varying  in  this  respect  from  nearly  north-west  to 
north-east,  or  north  70°  east. 

218.  The  descent  of  the  vein  is  never  direct  and  unbroken.    It 
is  made  up  of  many  nearly  isolated  sheets  or  tracts  of  mineral 
matter.     A  superior  tract  overlaps  the   inferior  in   front,  and  it 
thins  out  at  its  inferior  edge,  while  the  inferior  sheet,  at  its  superior 
edge,  falls  back  against  the  foot  wall. 

The  entire  sheet  of  a  vein  is  not  equally  rich  in  mineral  matter. 
Thus  the  auriferous  vein  of  Gold  Hill  is  traversed  by  rich  tracts 
of  auriferous  metal,  which  alternates  with  poor  tracts.  This  is 
true  of  veins  in  Europe.  It  is  necessary  in  such  cases  to  find  the 
rich  auriferous  tracts.  The  gold  is  not  entirely  absent  in  the  other 
parts  of  the  sheet — they  are  simply  poorer.  None  of  the  metals 
appear  to  be  confined  to  a  certain  rock.  Gold,  for  example,  occurs 
in  the  argillaceous  and  talcose  slates ;  in  hornblende  and  serpentine, 
though  rarely,  and  sometimes  in  a  limestone  gangue;  and  it  is 
found  in  remarkably  rich  deposits  in  quartz  rock  of  sedimentary 
origin,  which  is  equivalent  to  the  quartz  rock  of  Berkshire  Co., 
23 


266  MANUAL   OF   GEOLOGY. 

Mass.  The  presence  of  metals  seems  frequently  at  least  to  be 
dependent  upon  a  store  of  the  material  in  the  region  beneath.  The 
same  rocks  which  are  metalliferous  on  the  east  side  of  the  Blue 
Ridge,  are  less  so  on  the  west  side. 

Veins  differ  in  Age. — Most  of  the  metals  are  found  in  the  pyro- 
crystalline  rocks,  and  when  the  veins  occur  in  sediment  they  are 
not  removed  very  far  from  them. 

219.  Fissures  are,  no  doubt,  filled  in  different  modes.  The 
matter  which  fills  a  fissure  must  have  been  either  liquid  or  aeriform, 
the  material  being  always  crystalline,  and  frequently  in  the  condi- 
tion of  perfect  crystals.  Hence  it  is  probable  they  are  filled  from 
beneath,  and  not  by  sediments  washed  in  from  above. 

It  is  not  difficult  to  conceive  that  a  fissure  which  extends  to  that 
depth  where  the  materials  are  molten,  that  the  forces  generated 
there  would  be  sufficient  to  fill  the  fissure  with  liquid  matter. 
Dykes,  no  doubt,  are  filled  with  matter  in  this  condition,  the  fissure 
extending  to  the  depth  required.  But  it  is  more  consonant  with 
facts,  and  the  nature  of  metalliferous  lodes  or  veins,  to  infer  that 
the  sulphurets  and  chlorides  especially  have  been  introduced  in  the 
condition  of  vapor,  the  fissure  becoming  really  a  gallery  of  sublima- 
tion. This  view  is  sustained  by  arguments  derived  from  the  incan- 
descent state  of  the  interior.  But  fissures  exist  which  might  be 
termed  blind  fissures ;  that  is,  they  are  neither  connected  with  the 
incandescent  part  beneath,  nor  the  earth's  surface  above.  A  fissure 
with  no  opening  in  any  direction,  will  not  remain  empty.  To  such 
a  point  the  hygrometric  water  of  the  rock  will  tend,  bearing  its 
most  soluble  matters  in  solution.  Such  a  fissure  would  be  a  vacuum, 
and  hence  could  not  fail  to  receive  and  also  be  filled  with  the  solu- 
ble matters  in  the  course  of  time.  The  filling  of  such  cavities  is 
usually  regarded  as  due  to  an  electric  agency,  which,  it  is  supposed, 
may  operate  through  a  considerable  mass  of  rock. 

Veins  are  irregular  in  width ;  sometimes  enlarging  to  twice  or 
thrice  their  average  width,  or  they  may  contract. 

Veins  are  shifted  also  from  their  regular  range  or  direction.  The 
shifted  parts  frequently  preserve  their  parallelism.  Dykes  are  usu- 
ally found  crossing  those  veins  when  thus  thrown  out  of  their 
regular  strike. 


CHAPTER  XXIV. 

MEAN  ELEVATION  OP  LAND — OCEAN  LEVEL — DISTURBANCES,  OR 
DISLOCATIONS  OF  THE  EARTH'S  CRUST — EPOCH  OF  SOME  OF  THE 
MOST  IMPORTANT  DISLOCATIONS — GRADUAL  AND  PAROXYSMAL 
ELEVATIONS — RELATIONS  OF  LAND  AND  WATER — CHANGES  OF 
TEMPERATURE  INDUCED  BY  A  CHANGE  OF  RELATIONS,  AND 
EFFECT  ON  THE  DISTRIBUTION  OF  PLANTS — THE  RELATIONS  OF 
IGNEOUS  ROCKS  TO  DISTURBANCES  OF  THE  EARTH'S  CRUST. 

220.  Mean  Elevation  of  Land  and  Ocean  Level. — The  first 
impression  respecting  the  mean  elevation  of  land  above  the  level 
of  the  ocean,  probably  is  that  it  is  much  greater  than  the  truth,  as  it 
is  known  that  some  points  of  the  Himalaya  and  Andes  rise  from 
twenty-five  to  twenty-eight  thousand  feet.  This  impression  is  sub- 
sequently corrected  by  the  consideration  that  the  area,  which  is 
covered  by  water,  is  more  than  three  times  greater  than  that  of  the 
dry  land,  especially  when  taken  in  connection  with  another  fact, 
that  the  mountain  areas  are  less  than  one-half  that  of  the  level 
and  undulating  parts  of  its  surface.  Certain  small  tracts  of  land 
are  beneath  the  level  of  the  ocean,  as  the  valley  of  the  Jordan  and  the 
Dead  Sea,  the  latter  of  which  is  some  1300  feet  below  the  level  of 
the  Mediterranean.  But  the  few  instances  of  extreme  depths  of 
gorges  of  this  kind  affect  but  slightly  general  results,  or  the  gene- 
ral conditions  of  the  earth's  surface.  The  mean  elevation  of  surface 
for  England,  Wales,  and  Scotland  is  about  500  feet.  It  is  estimated, 
however,  that  the  mean  elevation  of  land  for  Asia  and  America, 
in  round  numbers,  is  about  2000  feet.  This  estimate,  however, 
is  probably  too  great.  The  ancient  doctrine,  once  quite  prevalent, 
that  the  level  of  the  ocean  was  inconstant,  and  subject  to  great 
fluctuations,  has  given  place  to  the  more  consistent  view,  that  its 
variations  in  level  are  but  slight,  or  so  limited,  indeed,  that  no  varia- 
tion can  be  detected  beyond  the  rise  of  tides;  hence  the  mean 
level  of  all  oceans  is  a  constant,  of  a  given  value,  and  subject  to 
no  perceptible  variation,  while  the  elevation  of  land  is  a  variable 

quantity. 

(267) 


268  MANUAL   OF   GEOLOGY. 

The  elevation  of  land,  however,  is  not  so  great  but  that  its  whole 
area  might  be  covered  with  water;  and  were  all  the  continents  sub- 
merged, the  ocean  level  would  not  be  raised  five  hundred  feet 
above  its  present  tidal  line. 

221.  Disturbances,  or  Dislocations  of  the  Earth's  Crust. — The 
elevation  of  land  is  no  doubt  due  to  the  action  of  forces  beneath. 
This  view  is  suggested  by  many  well-determined  facts ;  for  exam- 
ple, the  immediate  connection  of  intense  volcanic  action  with  moun- 
tain chains,  and  the  phenomena  of  the  invariable  increase  in  the 
number  and  extent  of  dislocations  as  we  approach  the  axes  of  the 
mountain  systems.     One  of  the  general  effects  of  dislocation  and 
disturbance  of  the  earth's  crust  is  to  displace  the  ocean ;  for  exam- 
ple, the  effect  of  the  elevation  of  the  great  Rocky  Mountain  range 
has  been  to  displace  the  Atlantic  from  its  base  and  the  Mississippi 
Valley.     The  Atlantic  has  therefore  travelled  eastward,  in  conse- 
quence of  which  North  America  has  been  reclaimed  from  the 
dominion  of  its  waters. 

222.  The  epochs,  when  dislocations  have  taken  place,  is  well 
worth  our  attentive  study.    That  there  have  been  periods  of  intense 
intestine  commotion,  which  has  resulted  in  fractures  of  the  earth's 
crust,   and  which  has  been  followed  by  periods  of  rest,  is  well 
determined.     The  general  result  of  inquiry  is,  that  mountain  sys- 
tems have  been  formed  at  different  epochs.     Some  are  much  older 
than  others,  and,  what  is  remarkable,  the  highest  of  our  mountain 
systems  upon  the  globe  are  the  youngest.    The  Alps  and  the  Him- 
alayas belong  to  the  Tertiary  epoch,  while  our  Alleghanies  belong 
to  a  period  just  subsequent  to  the  Carboniferous.     The  later  dis- 
turbances may  affect  all  the  previous  systems  of  rocks.     It  will  be 
upon  the  upturned  edges  then  of  the  older  masses  that  new  depo- 
sits of  sediments  will  be  formed. 

The  disturbance  which  elevated  the  Carboniferous  rocks  of  Penn- 
sylvania, and  even  placed  the  older  in  a  leaning  position  upon  the 
newer,  affected  the  whole  series  of  rocks  in  the  valley  of  the  Hud- 
son, and  caused  the  slates  to  override  each  other.  Phenomena  of 
this  kind  may  be  witnessed  in  the  streets  of  Troy,  and  the  railroad 
cuttings  in  the  vicinity  of  Albany.  The  Devonian  of  Pennsylvania 
at  Pottsville  rests  or  leans  upon  the  coal  measures. 

The  most  ancient  disturbance  which  occurred  in  the  sedimentary 
period,  was  just  subsequent  to  the  termination  of  the  Taconic 
epoch.  This  is  evident  from  the  fact  that  the  oldest  members  of 


ETC.  269 

the  Silurian  rocks  rest  upon  the  upturned  edges  of  the  Taconic 
series  throughout  the  upper  part  of  the  valleys  of  the  Hudson  and 
•Lake  Champlain. 

During  the  Tertiary  period  the  disturbances  which  affected  the 
Atlantic  coast  may  be  regarded  simply  as  oscillations  of  the  land. 
The  most  important  or  most  extensive  movements  of  the  earth's 
crust,  within  the  time  specified,  were  in  immediate  connection  with 
the  Drift  period.  These  movements  have  already  been  described. 

In  considering  the  character  of  these  movements,  we  can  scarcely 
avoid  the  conclusion  that  some,  at  least,  were  violent  and  paroxysmal, 
though  in  the  later  periods  they  were  quite  limited,  and  resemble 
those  which  occur  during  earthquake  movements,  an  example  of 
which  was  witnessed  in  Chili,  in  1822,  when  its  coast  was  elevated 
ten  feet  for  one  hundred  miles  at  least.  The  valley  of  Lake  Cham- 
plain  presents  phenomena  which  indicate  paroxysmal  movements 
in  lines  of  parallel  ridges,  and  which  point  to  the  former  levels  of 
the  waters  which  occupied  the  present  valley. 

223.  We  have  already  alluded  to  the  fact  that  the  dry  land  is 
variable  in  position  and  height,  and  that  these  changes  occur  with- 
out affecting  the  mean  level  of  the  ocean.  It  is,  however,  impor- 
tant to  state  that  such  changes  exert  considerable  influence  upon 
the  temperature  of  a  country.  The  snow-line  of  continents,  or  the 
line  of  perpetual  frost,  is  about  15,000  feet,  under  the  equator, 
above  the  level  of  the  sea.  This  line  constantly  approaches  the 
earth's  surface  towards  the  poles.  But  the  rate  of  approach  to  the 
earth  is  influenced  by  the  nature  of  the  surface.  High  land  causes 
it  to  descend  more  rapidly  than  plains,  and  especially  if  the  sur- 
face is  covered  with  water.  Water  surface  is  favorable  to  the  pro- 
duction of  moderate  temperatures  j  and  as  a  water  surface  favors 
also  a  moist  atmosphere,  the  kind  of  vegetation  grows  out  of  cer- 
tain combinations  of  land  and  water  surfaces. 

In  accounting  for  the  distribution  of  plants,  however,  it  is  neces- 
sary to  consider  dry  ness  as  well  as  temperature  and  moisture. 
Certain  plants  occupy  certain  zones  of  height  and  latitude.  It  is 
found  that  height  compensates  for  latitude,  and  that  what  are 
termed  Alpine  plants  occur  also  in  high  latitudes.  Saxifrages  and 
mosses  flourish  upon  mountain  slopes  and  high  latitudes.  Northern 
woods  furnish  birches,  beeves,  pines,  and  willows.  High  meadows, 
the  gramineas  and  the  cyperaceae,  or  the  coarser  grasses.  Such 
23* 


270  MANUAL   OP   GEOLOGY. 

facts  are  important  elements  in  geological  inductions,  but  we  have 
no  space  to  dwell  particularly  upon  the  subject. 

224.  The  geographical  areas  of  belts  or  zones  of  disturbances 
often  seem  to  be  connected  with  the  distribution  of  certain  igneous 
rocks.     Thus  the  green-stones  of  the  Trias  form  a  prominent  fea- 
ture of  the  period  in  this  country.    The  Palisadoes  of  the  Hudson, 
the  traps  of  Mount  Holyoke  and  the  Connecticut  Valley,  are  con- 
nected with  disturbances  and  oscillations  of  this  epoch.     These 
igneous  rocks  form  a  less  bold  feature  in  Virginia  and  North  Caro- 
lina, but  still  they  traverse  the  same  series  in  heavy  dykes.     The 
anthracite  region,  however,  of  Pennsylvania,  though  greatly  dis- 
turbed, appears  to  be  an  exception  to  the  rule.     We  find  neither 
granite  nor  trap  in  immediate  connection  with  the  coal  measures. 
So  distant  are  the  masses  of  igneous  rocks  that  it  is  unphilo- 
sophical  to  attribute  the  debituminization  of  the  coal  to  the  pre- 
sence of  this  class  of  rocks,  or  to  the  agency  of  heat  in  the  interior 
of  the  earth. 

225.  The  general  distribution  of  heat  upon  the  earth's  surface 
is  not  altogether  controlled  by  latitude.     The  mean  temperature  of 
a  given  degree  of  latitude  in  Europe  is  higher  than  that  of  the 
same  latitude  in  America.    Lines  of  equal  temperature,  in  Europe, 
when  prolonged  to  this  continent,  turn  southward,  and  change  their 
direction  at  least  10  degrees.     Lines  indicating  equal  temperatures 
are  called  isothermal. 

226.  The  distribution  of  animals  is  governed  in  part  by  tempe- 
rature.    Climatal  conditions,  however,   embrace   many  elements. 
All  parts  of  the  earth's  surface  bring  forth  plants.    Marine  animals 
occupy  greater  ocean  depths  than  plants. 

The  occurrence  of  large  fossils  and  animals  in  northern  latitudes 
was  an  enigma,  until  it  was  discovered  that  they  were  provided  with 
a  covering  suitable  to  their  habits  and  requirements.  Thus,  the 
extinct  Siberian  elephant  was  covered  with  a  dense  coat  of  coarse 
wool  and  hair;  and  hence,  too,  we  may  conclude  that  fossil  species 
were  as  well  provided  for  as  those  which  are  familiar  to  us,  and 
belong  to  our  own  times. 


CHAPTER  XXV. 

SOILS. 

227.  SOILS  are  mixtures  of  earths,  oxides,  salts,  and  vegetable 
mould,  or  matters  derived  from  decomposed  organic  substances,  to 
which  we  may  add  water  and  air.  As  a  body,  then,  they  may  be 
divided  into  inorganic  and  organic  parts ;  the  former  being  derived 
exclusively  from  the  rocks  by  disintegration,  the  latter  from  the  vege- 
table and  animal  kingdoms;  carbonic  acid  and  ammonia  were  derived 
from  the  mineral  kingdom.  The  saline  bodies  consist  of  earthy 
and  metallic  bases,  combined  with  acids,  which  are  derived  from 
the  mineral  and  organic  kingdoms.  Phosphoric  acid  is  no  doubt 
derived  originally  from  the  mineral  kingdom ;  but  in  soils  its  proxi- 
mate source  may  be  either  the  animal  or  vegetable  kingdom,  or 
both,  in  a  single  sample  of  soil.  Soils,  therefore,  possess  a  complex 
composition,  consisting  of  a  large  number  of  bodies,  mixed  in  part 
mechanically,  and  in  part  in  chemical  combination.  The  inorganic 
matters  usually  predominate  greatly  over  the  organic,  and  of  these 
silica  exists  in  the  greatest  proportion.  To  the  eye  soils  appear 
inert ;  but  we  may  well  believe,  from  results  which  we  witness, 
that  they  continually  undergo  chemical  changes,  to  which  some  of 
the  most  important  results  to  the  agriculturist  are  due. 

As  the  origin  of  soils  is  ascribed  to  rocks,  it  will  at  once  be  ex- 
pected that  their  nature  or  composition  will  partake  of  those  mate- 
rials which  are  regarded  as  their  source.  This  is  no  doubt  true  in 
many  instances.  But  it  happens  that  soils  have  been  moved,  and 
do  not  always  rest  upon  the  rock  from  which  they  were  derived ;  and 
hence  the  exact  materials  which  enter  into  their  composition  cannot 
be  decided.  Soils,  unless  the  most  recent,  are  rarely  in  exact  situ. 
The  rains,  creating  a  surface  drainage,  move  the  lighter  parts  of 
soil  towards  the  valleys,  where  they  have  been  subjected  to  slow 
movements  for  a  long  time.  They  finally  reach  the  valleys,  and  are 
there  spread  Out. 

But  the  soils,  which  are  now  spread  over  a  large  part  of  this 
country,  have  been  subjected  to  a  more  violent  movement  than  we 

(271) 


272  MANUAL   OF    GEOLOGY. 

have  just  indicated.  Thus  all  of  New  England,  New  York,  soils 
and  those  of  the  Western  States,  on  the  east  side  of  the  Rocky 
Mountains,  have  been  transported  from  north  to  south  to  a  distance 
which  has  placed  them  far  beyond  the  limits  of  the  rocks  from 
which  they  are  derived.  The  effect  of  this  movement  has  been  to 
mix  and  blend  soils  from  the  different  rocks.  This  movement 
occurred  in  the  Glacial  epoch,  of  which  we  have  already  spoken. 
But  it  did  not  affect  large  territories  in  the  Southern  and  South- 
western States.  Hence,  the  soil  in  these  states  is  very  nearly  in 
situ,  having  been  subjected  to  those  changes  only  which  are  due  to 
common  occurrences.  It  is  in  this  part  of  our  country,  then,  that 
the  composition  of  soils  partakes  of  that  of  the  rock  beneath ;  inas- 
much as  they  were  derived  from  it,  have  not  been  moved  far,  nor 
intermixed  with  foreign  materials. 

One  important  result  has  grown  out  of  the  foregoing  fact :  the 
rock  having  been  subjected  to  the  action  of  those  agents  which  pro- 
duce disintegration  for  a  long  time,  beds  of  soil  of  great  thickness 
have  been  formed.  The  time  during  which  these  beds  have  been 
accumulating  cannot  be  determined  with  accuracy ;  but  the  process 
commenced  before  the  last  upheaval  of  the  coast,  but  since  the 
Pliocene  period.  We  are  able  to  trace  this  formation  of  soil,  by 
its  peculiar  red  color,  to  the  Tertiary  section  of  North  Carolina ; 
and  we  find  it  overlying  all  marine  deposits,  except  the  last  stratum 
of  sand  and  pebbles,  the  latter  of  which  is  marine,  and  forms  a 
mantle  over  all  the  deposits  of  the  eastern  section  of  the  Southern 
States.  This  red  layer  of  soil,  which  is  derived  from  the  rocks  of 
the  middle  section  of  these  states,  may  be  traced  many  hundred 
miles,  and  it  always  occupies  the  same  relative  position. 

From  the  nature  of  the  origin  of  soils,  from  their  natural  expo- 
sures, and  especially  from  cultivation,  it  is  plain  their  composition 
must  vary  exceedingly. 

228.  For  many  valuable  purposes  we  may  make  a  geographical 
division  of  them. 

1.  Soils  of  the  sea  coast.  2.  Soils  of  'interior ',  occupying  plateaus, 
and  dry  slopes.  3.  Soils  of  valleys,  embracing  the  alluvium  of 
rivers. 

1.  Coast  Soils  of  Marine  Origin. — In  the  Southern  States, 
beyond  the  action  of  the  forces  displayed  during  the  Glacial  epoch, 
the  soils  may  be  divided  into  sands,  clays,  mixtures  of  these  ele- 


SOILS.  273 

ments,  and  those  of  vegetable  origin  in  part,  together  with  a  mix- 
ture of  vegetable  matter  and  sand;  with  some  clay. 

The  sands  occupy  the  surface  of  large  tracts  of  country,  as  the 
pine  barrens;  but  while  the  surface  was  still  covered  with  the  ocean, 
or  at  the  time  of  its  recession,  large  tracts  of  surface  materials  were 
carried  away,  and  the  country  was  denuded  down  to  a  bed  of  marine 
clay.  The  marine  clay  is  on  the  east  side  of  the  heavy  beds  of 
sand,  which  presents  an  undulating  surface  not  unlike  the  sea  when 
agitated.  These  sands  contain  from  88  to  95  per  cent,  of  silex,  or 
rather  sand,  in  rounded  particles.  Often  they  are  pure  enough, 
after  washing,  for  glass,  perhaps  with  the  exception  of  some  mag- 
netic iron  sand.  This  sand  is  more  or  less  intermixed  with  vegeta- 
ble mould,  and  even  in  its  poor  condition  supports  a  forest  of 
long-leaved  pine.  But  it  does  not  bear  cultivation ;  and  when  put 
under  the  plough  it  soon  wears  out  and  blows  into  ridges,  and  whole 
regions,  underlaid  with  these  sands,  would  drift  and  become  mova- 
ble sand  banks.  When,  however,  it  contains  clay,  it  is  compara- 
tively a  good  soil. 

229.  The  most  important  kinds  of  soil  are  those  in  which  vegeta- 
ble matter  is  very  large,  exceeding,  in  a  few  instances,  90  per  cent. ; 
that  is,  it  becomes  strictly  peat.     But  the  percentage  of  vegetable 
matter  is  variable,  and  when  it  does  not  exceed  75  per  cent.,  and 
is  intermixed  with  from  10  to  25  per  cent,  of  earth,  it  forms  the 
best  of  soils.    Soils  composed  of  this  large  percentage  of  vegetable 
matter  can  be  found  only  in  swamps. 

There  are  two  kinds  of  swamp  lands ;  the  first  has  its  due  pro- 
portion of  earth,  as  the  swamp  lands  of  Hyde  and  Onslow,  North 
Carolina ;  the  second  has  too  small  a  proportion  of  earth  to  admit 
of  tillage,  as  the  open  prairie  of  Carteret  county,  near  Beaufort. 

230.  The  composition   of  the  Hyde   county  lands   is   as  fol- 
lows : — 

Organic  mattter,           ........  48.10 

Silex, 43.00 

Oxide  of  iron  and  alumina, 6-40 

Carbonate  of  lime, 0.50 

Magnesia, 0.30 

Potash, 0.26 

Soda, 0.18 

Chlorine, trace 

Soluble  silex, ,  0.03 

Sulphuric  acid,             0.04 

Phosphoric  acid, 0.60 

99.31 


274  MANUAL   OP   GEOLOGY. 

The  inorganic  matter,  after  the  removal  of  the  organic,  is  ex- 
tremely fine,  and  of  a  light  drab  color.  This  is  the  condition  of 
all  the  good  swamp  soils.  It  appears  to  have  been  originally  matter 
suspended  in  water,  and  these  swamps,  producing  the  ordinary 
growth,  sphaguums,  mosses,  &c.,  were  often  covered  with  water 
arising  from  freshets  in  the  neighboring  streams,  and  which  then 
overflowed,  depositing,  during  the  time,  a  fine  sediment  amidst  the 
marsh-growing  vegetables.  This  variety  is  therefore  of  fresh-water 
origin.  But  the  open  prairie  land,  or  soil,  is  swamp,  less  advanced, 
or  received  no  sediments  from  the  rise  of  rivers ;  or,  in  other  words, 
they  were  never  overflowed  with  waters  charged  with  debris,  or 
sediments;  they  contain  or  produce  the  coarse  vegetables  and 
grasses,  but  have  no  earth  or  soil  proper. 

Associated  with  the  foregoing  we  believe  it  possible  to  recognise 
another  variety  still,  which  was  due  to  marine  influences.  Thus, 
a  poor  soil,  consisting  of  a  white  sand  intermixed  with  black  vege- 
table matter,  is  common  in  the  low  counties  of  North  Carolina  and 
other  Southern  States.  It  looks,  before  cultivation,  like  the  former, 
but  in  a  few  years  it  becomes  decidedly  sandy ;  the  black  mould  is 
burnt  out,  and  the  marine  sand  begins  to  blow  into  ridges.  It  is 
unproductive  after  a  few  years  of  cultivation. 

231.  The  marine  clays  and  mixtures  of  sand  resemble,  in  all 
respects,  the  clays  of  the  uplands.     They  are  good  wheat  soils, 
while  certain  varieties  of  the  swamp  lands  are  the  best  for  Indian 
corn,  producing  steadily  from  fifty  to  sixty  bushels  per  acre  per 
annum  for  a  century,  without  the  use  of  fertilizers. 

232.  The  soils  of  the  interior,  occupying  terraces  and  slopes, 
are  usually  dry,  gravelly,  and  silicious.     The  terraced  valleys  of 
the  rivers  of  New  England  and  New  York,  the  bluff  formation  of 
the  river  valleys  of  the  Western  States,  possess  these  common  cha- 
racters.    They  are  formed  in  some  instances,  by  the  gradual  dis- 
placement of  the  soil  from  the  steep  hillsides,  and  accumulating 
in  the  valleys ;  but  being  in  the  direction  of  a  watercourse,  they 
are  cut  through,  and  worn  down  in  process  of  time,  leaving  the 
lateral  parts  of  the  beds  standing  in  the  form  of  terraces  and  bluffs. 
The  bluff  soils  and  terraces  are  sometimes  the  recipients  of  springs 
from  the  mountain  sides,  and  hence  they  are  less  productive  at  first, 
being  too  cold  for  the  best  grasses,  or  for  the  cereals.     Drainage  is 
necessary,  and  is  easily  effected.     It  cures  the  dilficulty,  and  these 
terraced  valleys  become  the  most  valuable  soils  of  the  country. 


SOILS.  275 

233.  The  productiveness  of  all  soils  depends  upon  the  presence 
of  all  the  elements  enumerated  in  the  foregoing  analysis.     But  the 
farmer  or  planter  is  under  no  necessity  of  supplying  but  a  few  in 
this  list.     Of  those  which  disappear  after  cultivation,  the  alkalies 
and  alkaline  earths,  and  phosphoric  acid,  are  the  most  important. 
These  never  exist  in  large  quantities.     It  appears,  too,  from  obser- 
vation and  experiment,  that  they  may  exist  in  the  soil  in  such  a 
state  of  combination  that  they  are  inaccessible  to  the  roots  of  plants, 
or,  in  other  words,  are  locked  up.    The  atmospheric  agencies,  how- 
ever, are  always  at  work,  and  when  a  soil  is  allowed  to  rest,  they 
accumulate  in  perceptible  quantities. 

The  productiveness  of  any  soil  is  affected  by  its  temperature.  Wet 
soils  are  unsuitable  for  the  cultivation  of  the  cereals.  Hence  the 
necessity  of  drainage. 

234.  The  temperature  of  any  soil  is  due  to  solar  influence.     It 
is  continually  changing  in  this  respect.     Its  temperature  begins  to 
rise  in  the  spring,  and  continues  to  rise  until  about  the  middle  of 
August,  in  the  latitude  of  Albany,  when  it  gradually  declines.     It 
is  affected  differently  at  different  depths,  undergoing  the  greatest 
change  near  the  surface.     These  changes  are  well  exhibited  in  the 
annexed  table.  (Fig.  218.)    The  observations  were  made  at  Albany 
for  three  years  in  succession  by  myself,  and  the  results  are  expressed 
in  the  mean  for  every  two  weeks  during  the  year  1847. 

235.  There  is  still  another  condition  which  greatly  influences  the 
productiveness  of  soils.     It  is  the  quantity  of  water  which  they 
receive  from  the  atmosphere. 

The  usual  quantity  of  vapor  or  water  contained  in  a  cubic  foot 
of  air,  is  four  grains,  which  is  equivalent  to  a  pint  in  a  room  fifteen 
feet  square  and  eight  feet  high.  A  column  of  atmosphere  over 
each  acre  of  land  holds  one-fourth  millions  of  gallons  in  its  normal 
state,  without  feeling  damp,  or  having  a  tendency  to  fall  in  mist  or 
dew.  But  this  quantity  may  be  increased  in  different  parts  of  the 
columns.  Thus,  during  the  warmth  of  summer  temperature  (70°), 
it  may  be  doubled,  or  increased  to  eight  grains  to  the  cubic  foot, 
while  in  winter  it  is  less  than  four  grains.  If  we  assume  a  limited 
thickness  of  the  atmosphere,  each  yard  of  height  of  a  column 
whose  base  is  one  acre  may  contain  no  less  than  sixteen  gallons  of 
water;  and  by  change  of  temperature  this  power  of  retaining  water 
may  be  rapidly  reduced  to  the  normal  standard,  four  gallons. 
Twelve  gallons  may  thereby  be  discharged  in  a  short  time  upon  the 


276 


MANUAL   OF   GEOLOGY 


Semi-monthly  observations  on  the  mean  temperature  of  the  foil  at  Albany,  taken  at 
different  depths,  for  1847:  viz..  air  represented  by  a  continuous  line;  two  feet 
and  four  feet,  by  dotted  lines.  The  marginal  numbers  are  the  degrees  of  tempera^ 
ture.  Months  at  the  head  of  the  columns. 

Fig.  218. 


75 


70 


Air 

*  ft. 


~r 


SOILS.  277 

surface  of  an  acre.  But  clouds  are  well-known  accumulators  of 
vapor,  which  is  originally  dissolved  in  transparent  air,  but  becomes 
visible  by  partial  condensation.  An  acre  of  cloud,  five  hundred 
yards  thick,  may  discharge  any  quantity  of  water,  up  to  six  thou- 
sand gallons,  provided  the  air  in  regard  to  temperature  varies  from 
70°  to  40°. 

If  a  cloud,  five  hundred  yards  thick,  moves  at  the  rate  of  three 
miles  an  hour,  and  deposits  one  twenty-fifth  part  of  its  available 
water,  there  will  be  a  shower  of  rain,  and  the  quantity  marked 
upon  the  rain-gauge  will  correspond  to  one  inch,  and  will  therefore 
amount  to  twenty  thousand  gallons  to  each  acre  which  it  passes 
over  at  the  assumed  rate  of  three  miles  to  the  hour. 

The  quantity  of  water  in  a  soil  varies  very  much  with  its  com- 
position. Sandy  ones  contain  less  than  clay  soils,  but  a  soil  well 
constituted  as  to  fertilizing  matter,  is  always  tenacious  of  moisture. 
The  most  tenacious  of  water  are  those  which  contain  a  large  inter- 
mixture of  very  fine  organic  matter;  next  to  these  are  the  marly 
clays.  The  moisture  or  water  of  soils  may  be  husbanded  by  early 
planting,  or  by  securing  an  early  growth  of  the  plant  sufficient  to 
cover  and  shade  the  surface  during  a  time  of  drought. 

236.  Soils  may  be  too  fine  to  be  productive,  on  the  ground  that 
their  compactiveness  excludes  the  access  of  air.     The  extremely 
fine-grained  soils,  formed  from  sediments  alone,  would  be  too  com- 
pact if  not  intermixed  with  organic  matter,  as  those  of  Hyde  county, 
North  Carolina,  and  certain  soils  of  the  Western  States.     Coarse 
soils,  as  those  of  some  of  the  New  England  States,   decompose 
slowly,  and  may  furnish  in  a  given  time  too  small  a  quantity  of 
potash  and  phosphoric  acid,  and  the  other  expensive  elements,  for 
steady  cultivation.     They  require  rotation  and  rest.     The  effect  of 
stones  in  a  soil  is  to  condense  moisture  and  preserve  it  in  a  favora- 
ble condition  for  the  growth  of  vegetables. 

237.  Certain  green  crops,  used  as  manures,  bring  to  the  surface 
the  expensive  elements  which  are  beyond  the  reach  of  the  roots  of 
cereals.     Clover  roots,  as  well  as  the  southern  pea,  send  their  root- 
lets deep,  and  thereby  open  the  soil. 

238.  Ploughing,  when  the  soil  is  wet,  is  injurious,  because  the 
soil  breaks  up  in  large  coherent  lumps,  which  become  hard  on  dry- 
ing, and  an  entire  season  is  required  to  break  them  down. 

Deep  ploughing  brings  up  virgin  soil  nearer  the  surface  where  it 
is  acted  upon  by  the  air,  and  better  prepared  to  furnish  nutriment 
to  the  plant. 
24 


278  MANUAL   OF   GEOLOGY. 

329.  Soils  of  Mountain  Slopes  absorb  Caloric. — Independent  of 
the  color  of  the  surface,  the  soils  of  mountains  become  warmer  by 
the  absorption  of  heat  than  those  of  plains  at  or  near  the  sea  level. 
Hence,  the  snow  melts  which  is  in  immediate  contact  with  the 
earth,  and  forms  an  arch  (which  protects  Alpine  plants)  while  they 
bloom  and  perfect  their  seed.  So,  among  the  snow-covered  sum- 
mits, the  radiant  heat  melts  the  snow  beneath,  and  preparative  of 
a  sudden  descent  of  the  avalanche  upon  the  plains  below. 

Even  the  hill-sides  of  New  England  become  green  at  an  earlier 
day  in  the  spring  than  the  low  meadows  which  surround  them.  It 
is  in  consequence  of  the  law  of  the  absorption  of  heat,  by  moun- 
tain sides  and  slopes,  that  they  are  so  well  adapted  to  the  pasturage 
of  cattle,  and  the  production  of  numerous  plants. 

The  effect  of  absorbed  heat  upon  vegetation  may,  however,  be 
counteracted  by  excessive  moisture.  This  state  arises  from  the 
numerous  springs  which  issue  from  mountain  sides :  the  surface 
water  being  absorbed  by  and  retained  in  the  soil,  preserves  it  in 
great  excess ;  and  hence,  when  it  evaporates,  it  cools  the  soil  by 
absorbing  its  extra  heat  it  has  absorbed  from  the  sun's  rays. 

240.  The  soil  derived  from  particular  rocks  is  to  a  limited  degree 
characterized  by  the  composition  of  the  parent  rock.  All  trap  rocks 
form  a  good  soil,  because  they  are  more  or  less  charged  with  alka- 
lies, alkaline  earths,  and  the  phosphate  of  lime.  So,  on  the  other 
hand,  granites,  which  are  coarse  and  contain  much  quartz,  make  a 
poor  soil,  because  its  texture  is  open,  and  the  soil  is  poor  in  the 
elements  furnished  by  trap;  and  yet  certain  granites,  rich  in  feldspar, 
make  good  soils.  These  may  be  known  by  their,  red  color,  which 
they  acquire  by  exposure  to  the  atmosphere.  As  a  general  rule  the 
soils  derived  from  granite,  gneiss,  mica  slate,  and  hornblende  rock, 
do  not  differ  essentially  in  composition.  0  The  soils  they  furnish  are 
generally  strong  and  durable.  The  mountain  soils  of  New  England 
furnish  many  varieties  and  examples.  They  are  excellent  for  grass, 
It  has  been  supposed  that  soils  which  rest  upon  limestone  are 
necessarily  charged  with  a  larger  percentage  of  lime  than  those 
which  rest  upon  gneiss  or  granite.  In  my  "  Agriculture  of  New 
York,"  I  have  shown  by  many  analyses,  that  this  is  not  the  case. 
But  it  is  to  be  recollected  that  all  parts  of  New  York  have  received 
large  instalments  of  drift,  which  has  been  derived  from  many  sources. 
The  drift  covers  limestone  as  well  as  gneiss.  But  there  is  a  class 
of  rocks  which  impart  their  own  character  to  soils  which  rest  upon 


SOILS.  279 

them.  They  are  the  fragile  slates  and  shales  which  are  constantly 
undergoing  decomposition ;  and  it  frequently  happens  that  the 
debris  which  is  thus  formed  is  reached  by  the  plough,  and  is  freely 
intermingled  with  the  old  and  partially-exhausted  matters.  Large 
tracts  are  common  in  the  Mohawk  Valley,  especially  in  Central 
New  York,  over  which  the  Clinton  and  Onondaga  salt  groups  are 
extended. 

241.  Climate  influences  soils,  however,  to  such  a  degree  that  they 
often  seem  to  lose  the  characteristics  derived  from  the  parent  rock. 
This,  however,  becomes  more  perceptible  after  long  cultivation. 
Where  the  climate  is  not  well  adapted  to  grass,  the  surface  is 
greatly  disposed  to  gully  and  wash.     Besides,  the  surface  is  liable 
to  be  carried  away  by  rains,  and  it  becomes  naked  and  presents 
a  barren  appearance.     Such  is  the  condition  of  large  tracts  in  the 
Southern  States.    The  gullies,  however,  are  often  created  by  a  wrong 
system  of  ploughing,  that  of  running  furrows  down  the  hill-side. 

One  of  the  most  important  points  to  be  seen  to  by  the  planter 
and  farmer,  is,  to  keep  the  surface  protected  by  vegetation.  More 
injury  is  done  to  a  soil  by  being  permitted  to  be  naked  and  exposed 
to  the  washing  by  rains,  than  by  a  judicious  cultivation. 

242.  Another  important  point  to  be  attended  to  in  cultivation,  is 
the  condition  of  the  soil  when  ploughed  as  to  the  presence  of  water. 
As  a  general  rule,  soils  filled  with  water  should  not  be  ploughed ; 
and  it  is  also  true  that  a  soil  in  very  dry  condition  should  not  be 
ploughed.     It  is  well  known  that  if  a.  soil  is  ploughed  when  wet, 
it  becomes  lumpy  and  hard,  and  the  effects  may  sometimes  be  seen 
for  two  or  three  years. 

243.  The  evils  attending  wet  soils  are  obviated,  at  least  in  part, 
by  deep   drainage.     The  effect  of  drainage  is  to   open  the  soil, 
increase  its  porosity,  anoj  make  the  heat  absorbed  from  the  sun's 
rays  useful  in  the  cultivation  of  the  most  valuable  crops.     To  the 
farmer  who  drains  his  lands,  spring  arrives  two  weeks  earlier  than 
to  his  neighbor  who  neglects  it.     But  the  results  of  drainage  are 
not  limited  to  the  spring ;  early  planting  secures  an  early  harvest. 
He  escapes  the  frosts  of  autumn,  while  the  drought  of  summer  is 
ameliorated  by  the  early  growth-  of  his  crops.     A  good  and  early 
stand  is  often  the  turning  point  of  the  planter's  hopes.     Ground 
which  is  shaded  by  corn  early  in  summer  rarely  suffers  destructively 
by  excessive  droughts. 


NOTES. 


NOTE  A.— p.  89. 

The  remarks  which  appear  in  the  Regent's  Report  of  New  York,  for  1859, 
require  a  brief  notice. 

The  slates  or  shales  referred  to  in  northern  Vermont,  as  constituting  a  new  series 
above  the  so-called  Hudson  River  group,  instead  of  ranking  thus  high  in  the  geo- 
logical scale,  are  really  sub-silurian,  as  is  fully  proved  by  the  overlying  calciferous 
sandstone.  The  latter  rock,  though  it  is  not  known  to  contain  fossils  in  this  part 
of  the  state,  yet  in  many  places  in  New  York  it  does;  particularly  a  species  of 
Maclurea  (Straparollus),  where  the  same  relations  exist  as  at  Bald  Mountain. 
The  mistake  arises  from  the  variable  character  of  the  calciferous  sandstone, 
though  its  general  aspect  is  preserved,  even  when  it  is  chocolate  colored,  and  it 
might  be  suspected  to  be  the  true  representative  of  this  silurian  member.  These 
colored  masses,  however,  pass  into  the  common  variety,  when  it  often  contains 
the  lower  silurian  fossils.  But  the  slate  has  never  furnished  a  silurian  species. 
We  now  know  the  following  trilobites,  all  of  which  belong  to  a  slate  beneath  the 
calciferous,  viz. :  Atops  punctatus,  eliptocephalus  (Paradoxides)  asaphoides,  Para- 
doxides  Thompsoni,  P.  Vermonti,  P.  macrocephalus,  Paradoxides  (Pagura) 
quadrispinosus,  and  Microdiscus  quadricostatus.  None  of  these  occur  in  the 
Hudson  River  slate  or  shales.  To  get  rid  of  difficulties,  it  is  said  in  the  report 
referred  to,  it  is  designed  to  make  a  new  group  of  strata,  which,  it  is  maintained, 
occupy  a  position  above  the  Hudson  River  shales.  The  impropriety  of  such  an 
arrangement,  must  be  admitted  by  all  candid  and  well-informed  geologists,  since 
the  calciferous  sandstone  overlies  this  slate. 


NOTE  B.— p.  190. 

It  is  maintained  by  a  few  distinguished  geologists,  that  the  life  of  correspond- 
ing ages  in  Europe  and  America  is  older  in  the  latter  than  in  the  former.  Before 
this  doctrine  is  accepted,  it  should  be  subjected  to  a  more  rigid  scrutiny  than  it 
has  yet  received;  for  down  to,  and  including  the  carboniferous  era,  there  are  no 
facts  which  countenVnce  this  assumption.  It  is  admitted  by  the  highest  authority 
that  the  carboniferous  era  corresponds  in  the  life  ages  in  the  two  continents. 
Progressing  downwards  another  great  stage,  the  Permian,  the  correspondence  is 
Btill  preserved.  A  comparison  of  the  cretaceous  system  of  Nebraska,  Kansas,  Texas, 

(280) 


NOTES.  281 

Alabama,  New  Jersey,  and  North  Carolina,  will  force  upon  geologists  the  conclusion 
that  a  correspondence  in  life  is  still  maintained  in  both  continents.  The  same 
conclusion  is  sustained  with  respect  to  the  miocene — a  conclusion  founded  in  part 
on  the  presence  of  fossil  plants  belonging  to  the  genera,  Populus,  Liriodendron, 
Laurus  Sapotacites,  &c.  This  conclusion  has  been  sanctioned  by  Professors 
Heer,  Leidy,  Marcou,  and  several  other  geologists  of  high  standing.  So,  also, 
in  the  formation  called  drift,  we  find  identical  fossils,  as  at  Quebec,  and  Udder 
valley,  in  the  north  of  Europe.  If,  then,  the  foregoing  conclusions  are  true,  it 
would  be  quite  remarkable  to  find  an  exception  in  the  Trias.  The  probability  is, 
that  on  both  continents  strata  of  considerable  thickness  may  and  do  exist  on  one 
continent,  which  are  not  represented  in  the  other,  even  when  a  formation  coin- 
cides generally  in  age. 


GLOSSARY  OF  SCIENTIFIC  WORDS. 


Abnormal.    Contrary  to  law.    An  unusual  developement  of  structure  or  form. 

Acephala,  Acephalous.  Without  a  head ;  a  Cuvierian  class  of  mollusks  or  shell- 
fish, as  the  oyster  and  clam. 

Acicular.    Needleform. 

Acrogens.     Plants  which  grow  from  their  summits,  as  the  ferns. 

Affinity.  In  Chemistry  it  is  that  force  by  which  elements  combine  and  form  new 
compounds.  In  Zoology  it  is  used  to  express  genealogical  relationship. 

Agamic.     Infertile,  as  the  ova  which  have  not  received  the  male  influence. 

Agate.  Uncrystallized  quartz  whose  parts  are  arranged  in  bands  of  different 
colors  and  shades. 

Agatized.    Arranged  in  bands  like  agate. 

Algce.     Cryptogamic  marine  plants  or  sea  weeds. 

Allotrophy,  Allotropism.  The  property  of  existing  in  two  or  more  states  or  forms, 
as  oxygen  in'  ozone  its  active,  and  common  oxygen  its  passive  state. 

Alluvium,  Alluvion,  Alluvial.  Beds  of  sand  and  gravel  which  are  now  accumu- 
lating along  the  banks  of  rivers  and  lakes. 

Alumina,  Pure  clay.  Aluminum,  The  metal  or  base  of  alumina.  Alum  stone,  A 
mixture  of  iron  pyrites  and  clay.  Shales  are  often  alum  stones. 

Amber.    A  fossilized  resin,  common  in  tertiary  beds. 

Ambulacra.  The  rows  of  holes  or  prominences  in  the  shells  of  Echini  or  Echino- 
derms. 

Ammonite.  An  extinct  genus  of  Cephalopoda.  They  have  coiled,  chambered 
shells. 

Amorphozoa.     The  sponges,  or  the  least  organized  class  in  the  animal  kingdom. 

Amorphous.     Devoid  of  a  regular  geometric  form  ;  uncrystallized. 

Amphibia.  A  class  of  animals  with  naked  skins,  as  the  frog,  toad,  and  sala- 
mander. 

Amphineust.  Reptiles  which  are  provided  with  both  lungs  and  gills,  as  the  siren 
and  proteus. 

Amphipoda.  A  small  tribe  of  crustaceans,  supplied  with  fourteen  slender  feet, 
similar  to  the  sand  flea. 

Amygdaloid.  A  porous  variety  of  trap ;  or  trap  which  had  originally  almond- 
shaped  cavities,  and  into  which,  in  process  of  time,  infiltrations  of  silica  and 
the  silicates  took  place,  as  agates,  carnelian,  phrenite,  Ac.,  Ac. 

(282) 


GLOSSARY.  283 

Analogize.    To  find  resemblances  between  things  belonging  to  diverse  types. 
Analogue.     The  theoretical  representatives  belonging  to  diverse  types ;  thus,  the 

order  Eaptores,  in  the  class  Birds,  are  the  analogues  of  the  highest  carnivora 

in  the  class  Mammals. 
Analogy.     In  Natural  History  it  is  the  similarity  in  function  which  exists  in 

organs  belonging  to  dissimilar  types,  as  the  fin  of  a  fish  and  the  wing  of  a  but- 
terfly, the  lungs  of  a  mammal  and  the  gills  of  a  fish ;  hence  it  is  said  there 

exists  an  analogy  between  the  gills  of  a  fish  and  the  lungs  of  a  mammal;  but 

there  is  no  homology. 

Anamorphosis.    The  changes  which  genera  undergo  in  their  course  through  time. 
Anatifa,  Anatifse.     Pedunculated  cirripeds ;   they  are  barnacles  supported  on 

stems  or  peduncles. 

Angiosperms.     Plants  whose  seeds  are  enclosed  in  a  capsule. 
Angle.    A  corner,  or  the  inclination  formed  by  the  meeting  of  two  or  more  planes 

or  lines. 

Aniaomeric.     Consisting  of  dissimilar  parts  ;  unsyminetrical. 
Antennse.     The  jointed  thread-like  organs  belonging  to  the  heads  of  insects. 
Anthozoa.     Marine  animals  resembling  flowers.     A  general  name  applied  to 

zoophytes,  coral,  &c. 
Anthracite.     A  hard,  debituminized  coal. 
Anthropoid.     Resembling  man.     Applied  to  monkeys  which  most  resemble  him 

in  externals. 

Anticlinal,  Anticlinal  axis.     The  dipping  of  strata  in  opposite  directions. 
Apod.     Without  feet. 
Araucaria.    Applied  to  a  family  of  pines,  mostly  confined  to  South  America  and 

New  Holland;  they  differ  in  structure  from  other  conifers  in  having  the  dots  in 

two  or  three  rows  arranged  alternately. 
Arborescent.     Branching  like  a  tree. 

Archetype.     The  perfect  representative  of  a  form  or  group  of  forms. 
Archimedes  Limestone.     One  of  the  subordinate  beds  of  the  lower  Carboniferous 

series. 

Arenaceous.     Sandy ;  a  friable  variety  of  quartz. 
Arenicolites.     Worm  holes  in  sand  and  sandstones. 
Argillaceous.     Clayey  ;  composed  in  part  of  clay. 
Articulata.     The  Second  Branch,  or  type,  of  the  Animal  Kingdom. 
Articulated.     Jointed. 

Asteroidea.     Starfishes;  an  order  of  Echinoderms. 
Atolls.    Coral  islands  of  a  circular  form,  and  which  are  bounded  by  a  rim  of  coral 

enclosing  a  lagoon. 

Atoms.     Particles  of  matter  which  cannot  be  further  subdivided. 
Avalanche.     Falling  masses  of  snow  from  mountain  peaks  or  sides. 
Azoic.     Without  life. 

Azoic  age.     An  age  prior  to  the  existence  of  life  upon  the  globe. 
Sack.     Miner's  term  for  joint. 
Bala  limestone.     In  Wales,  a  limestone  belonging  to  the  Cambrian  system  and 

equivalent  to  the  Trenton  in  New  York,  or  at  least  in  part. 
Basalt.     A  black,  compact  variety  of  trap  without  visible  particles  of  pyroxene, 

felspar,  or  hornblende. 
Base  line.    A  line  taken  as  the  foundation  of  operations  in  trigonometrical  and 

geological  surveys. 


284  MANUAL   OF   GEOLOGY. 

Basin.     A  depressed  area  with  the  strata  dipping  inwards. 

Bed.     A  layer  of  rock  of  a  uniform  character,  as  a  bed  of  coal,  clay,  or  sand. 

Bedding.     The  position  of  beds  in  a  group  of  rocks ;  the  bedding  may  vary  from 

the  horizontal  to  a  vertical  position. 
Belemnite.     An  extinct  genus  of  Cephalopods. 

Bench.  In  surveys,  a  selected  plane  or  bed  which  is  to  be,  or  may  subsequently 
be,  referred  to. 

Bi.     When  used  as  a  prefix  denotes  two  or  twice. 

Bilateral.     Having  a  right  and  left  side. 

Binomial  System  of  Nomenclature.  A  system  which  recognises  the  principle  of 
giving  two  names  to  objects  composing  the  kingdom  of  nature,  as  FELIS  tigris, 
ACER  riibrum,  &c.,  first  employed  by  Linnaeus. 

Bitumen,  Bituminous.  Mineral  pitch ;  a  highly  combustible  substance,  exhaling 
•when  burnt  a  peculiar  odor. 

Blastema.     The  primitive  basis  of  an  unformed  organ. 

Blende.     Blackjack  of  miners  ;  a  compound  of  sulphur  and  zinc. 

Bluff.  A  bold  bank  of  deposits  along  the  shore  of  rivers  and  lakes,  inclining 
steeply  on  the  water  side. 

Botany.     The  science  which  treats  of  plants. 

Bottom  Prairie.  A  formation  first  noticed  by  Prof.  Swallow ;  so  named  to  dis- 
tinguish it  from  the  high  land  prairie. 

Botryoidal.     Kesembling  a  bunch  of  grapes. 

Boulders.  Blocks  of  detached  rocks,  which  are  more  or  less  rounded  by  attrition. 
They  are  sometimes  called  travelled  rocks. 

Branches,  in  zoological  classification,  imply  the  four  grand  divisions  of  the  animal 
kingdom,  viz.,  Vertebrata,  Articulata,  Mollusca,  and  Radiata. 

Branchial.     Belonging  to,  or  serving  the  office  of  gills. 

Breccia.     A  mass  composed  of  cemented  angular  fragments  of  rocks. 

Bryology.     The  science  which  treats  of  the  true  mosses. 

Bryozoa.     Moss-like  animals ;  a  sub-class  of  mollusks. 

Buck.     In  mining,  to  break  or  pulverize  ores. 

Ctenozoic.  The  formations,  as  the  tertiaries,  which  contain  the  highest  organic 
bodies  or  remains.  As  the  mammals. 

Cainozoic.     Recent  life. 

Calcareous,  Calciferous.     Containing  lime. 

Calcareous  sinter.  Calc  sinter.  A  porous  deposit  from  spring  water  consisting 
of  lime  and  carbonic  acid. 

Calcareous,  or  Calcspar.     Crystallized  carbonate  of  lime. 

Cambrian  System.  A  name  proposed  by  Prof.  Sedgwick,  of  the  University  of  Cam- 
bridge, Eng.,  for  the  Lower  Silurian  System. 

Canon,  Canyon.     A  deep  gorge  bounded  on  each  side  by  steep  banks  or  clifis. 

Capsule,  Capstdiferous.     Bladder-like  organs  ;  bearing  capsules. 

Carapace.  The  shield  which  covers  the  back  in  turtles,  or  the  front  part  of  a 
crustacean. 

Carbon.  A  simple  combustible  body.  Coal  is  an  impure  example,  and  the  dia- 
mond is  pure  carbon. 

Carbonates.     Combinations  of  carbonic  acid  with  a  base,  as  lime,  iron,  lead,  Ac. 

Carboniferous.  Bearer  of  carbon ;  a  name  given  to  a  system  of  rocks  which  con- 
tain beds  of  coal. 

Carbonic  Acid.  A  gaseous  unrespirable  compound  of  oxygen  and  carbon ;  choke- 


GLOSSARY.  285 

damp  of  miners,  and  accumulates  in  dry  wells  and  depressions.  It  is  poisonous 
to  inhale,  and  suddenly  deprives  a  person  of  the  power  of  moving.  Dashing  a 
pailful  of  cold  water  upon  the  subject  is  the  true  remedy. 

Cataclysm.     A  violent  flood ;  a  deluge. 

Caucasian.  A  name  applied  to  the  white  races  of  man,  which  are  supposed  to 
have  originated  near  Mount  Caucasus ;  the  Indo-Europeans. 

Cell  development.  The  evolution  of  cells  or  growth  of  cells  in  organic  structures. 
A  reproduction  of  cells. 

Cellular.     Formed  of  cells,  and,  when  uncompressed,  appear  like  little  sacs. 

Centre  of  Gravity.     A  point  which  if  supported,  a  body  will  remain  at  rest. 

Cephalic.     Pertaining  to  the  head. 

Cephalopoda,  Cephalopoda.  Organs  of  motion,  feet  or  arms  arranged  around  the 
head.  A  class  of  mollusks  occupying  the  highest  rank  in  this  branch  of  the 
animal  kingdom. 

Cetacea.     Marine  mammals,  as  the  whale,  porpoise,  &c. 

Cetotolite.     Os  petrosum,  or  ear  bone  of  a  whale  in  a  fossil  state. 

Chalk.    An  earthy  limestone  occupying  the  upper  part  of  the  Cretaceous  System. 

Chalybeate.     Chalybeate  springs;  water  holding  iron  in  solution. 

Chambered.  Shells  which  are  provided  with  transverse  partitions,  as  the  am- 
monite. . 

Chert,  Cherty.  A  massive  silicious  rock  closely  resembling  flint;  mixed  with 
chert. 

Chemung  Group.  Rocks  of  the  Upper  Devonian  System,  and  which  take  their 
name  from  the  county  of  Chemung,  N.  Y. 

Chimerseridse.     A  family  of  sharks  with  cephalic  appendages. 

Chouteau  Limestone.  A  limestone  belonging  to  the  Upper  Devonian  System. 
Observed  in  Missouri,  and  first  described  by  Prof.  Swallow.  Occurs  in  Cooper, 
Boone,  and  Marion  counties,  Mo. 

Cilise,  Ciliated.  Minute  vibrating  organs  somewhat  like  hairs ;  furnished  with 
cilias. 

Cleavage.  The  property  of  splitting  with  regularity  in  certain  directions,  in  con- 
tradistinction from  breakage.  In  geology  it  is  often  applied  to  the  splitting 
of  slaty  rocks  in  a  direction  contrary  to  the  plane  of  deposition,  in  consequence 
of  which  the  cleavage  planes  are  often  mistaken  for  the  planes  of  deposition. 

Cliff  Limestone.  A  limestone  in  the  western  states  occurring  in  cliffs.  It  is 
found  to  be  an  erroneous  designation,  as  it  embraces  two  limestones.  One 
Devonian,  equivalent  to  Corniferous  limestone,  and  the  other  Silurian,  equiva- 
lent to  the  Calcareous  beds  above  the  Trenton. 

Climatic.     Pertaining  to  climate. 

Coal  Formation.     Any  series  of  rocks  containing  beds  or  seams  of  coal. 

Coalescent.    Joined  together ;  running  together. 

Compressed.     Flattened  sideways. 

Conformable,  Unconformable.  When  the  planes  of  different  strata  of  different 
ages  are  parallel,  they  are  said  to  be  conformable.  If  strata  rest  on  upturned 
edges,  they  are  unconformable.  Degrees  of  unconformity  exist.  / 

Conchoidal.     A  fractured  surface  resembling  the  curvatures  of  a  shell. 

Concretion.  A  mass  assuming  a  rounded  form,  whose  particles  combined  when 
the  rock  was  in  a  plastic  state. 

Condyle.  The  protuberances  at  the  base  of  the  skull  upon  which  the  head  moves 
in  a  vertical  plane. 


286  MANUAL   OF   GEOLOGY. 

Confervss.    Water  plants  which  consist  of  tubular  jointed  threads. 

Congeners,  Congeneric.     Species  which  belong  to  the  same  geuus. 

Conglomerates.  Beds  which  consist  mostly  of  pebbles,  and  which  have  passed 
into  a  consolidated  state  under  water. 

Conifers.    Cone-bearing  trees  whose  seeds  are  naked,  as  the  pines. 

Conjugation.  In  physiology,  it  is  the  sexual  union  of  the  infusoria  or  plants 
which  produce  spores ;  the  intermingling  of  the  contents  of  cells. 

Convolute.    Rolled  together  like  the  cypraea. 

Coriaceous.     Leathery. 

Corallum.     The  solid  or  calcareous  parts  of  a  polype. 

Correlation.  Having  reciprocal  relations.  Relations  of  things  and  beings  which, 
are  dependent  on  something  previously  existing ;  relations  of  the  son  to  the 
father  are  correlative. 

Cosmical.  Having  reference  to  the  universe  of  matter  and  the  harmonious  laws 
which  govern  its  movements ;  the  term  may  be  restricted  to  the  solar  system. 

Cosmogony.     Speculative  views  respecting  the  origin  of  the  globe. 

Costeaning.  A  Cornish  term  applied  to  a  particular  mode  of  searching  for  metal- 
lic bodies  j  as  the  sinking  of  shallow  pits,  or  driving  tunnels  across  the  forma- 
tion. 

Cotyledon.    In  botany,  the  lobes  6f  seed,  as  occurring  in  the  bean  or  pea. 

Crag.     An  English  term  for  a  shelly  deposit  of  the  tertiary  age. 

Crater.  The  funnel-shaped  opening  at  the  summit  of  a  volcano,  and  from  which 
volcanic  matters  issue  or  have  issued. 

Cretaceous,  Cretaceous  System.  Belonging  to  the  chalk ;  a  system  of  rocks  which 
closes  the  Mesozoic  period. 

Crop,  Crop  Out,  Outcropping.  The  appearance  at  the  surface  of  the  strata  of 
any  series  of  rocks.  They  sometimes  form  a  mere  selvage,  or  appear  at  their 
edges. 

Crustacea,  Crustaceous.  A  class  of  Articulates  which  are  covered  with  a  species 
of  corneous  crust,  as  crabs,  shrimps,  lobsters,  &c. 

Crust  of  the  Earth.     That  part  of  the  earth  which  is  accessible  to  observation. 

Cryptogamia,  Cryptogjamic,  Cryptogamous.  A  great  branch  of  the  vegetable  king- 
dom which  produces  spores  instead  of  seeds,  and  which  are  flowerless,  as  sea 
weeds,  mosses,  ferns,  and  lichens. 

Crystals,  Crystalline,  Crystallized.  Bodies  which  are  bounded  by  regular  geo- 
metric planes;  an  assemblage  of  coherent  grains  or  masses  of  rock  of  imperfect 
forms. 

Cycadese,  Cycads.  A  small  order  of  naked-seeded  plants  belonging  to  warm  cli- 
mates. Their  stems  are  short  and  stumpy,  with  pinnate  leaves,  and  inrolled 
like  the  ferns. 

Debacle.  A  rush  of  waters  carrying  forward  debris  and  broken  fragments  of 
rocks. 

Debris.  The  disintegrated  portions  of  rock  in  place,  or  moved  from  the  parent 
bed  by  frost  and  atmospheric  agents. 

Deduction.  In  logic,  that  which  is  drawn  from  premises.  A  conclusion  supported 
by  facts  or  principles. 

Deciduous.     Falling  of  organs  at  a  given  or  certain  period. 

Delta.  The  land  enclosed  by  the  forks  of  rivers  where  they  enter  the  sea,  and 
which  are  usually  of  a  triangular  shape. 

Dentine.     The  bony  part  of  teeth  directly  beneath  the  enamel. 


GLOSSARY.  287 

Denuded,  Denudation.  Rocks  or  surfaces  stripped  of  their  former  covering  by  a 
rush  of  waters. 

Depressed.     Flattened  from  above. 

Dermal.     Pertaining  to  the  skin. 

Desmidian.  A  family  of  microscopic  plants  of  a  green  color,  arranged  somewhat 
in  the  form  of  a,  chain. 

Determination.  The  application  of  the  characteristics  to  minerals  and  plants, 
fossils  and  rocks. 

Detritus.     Matter  worn  from  rocks  by  mechanical  action. 

Dextral.    Applied  to  shells  whose  spires  turn  from  east  to  south. 

Diatom.  A  microscopic  silicified  plant,  made  up  of  cells  divided  into  two  halves 
or  valves.  A  family  of  Diatoms. 

Dicotyledons.    A  grand  division  of  plants  whose  seeds  have  two  lobes. 

Dichotomom.    Dividing  into  two  branches. 

Didelphis.  A  marsupial  quadruped,  or  one  with  a  double  uterus,  one  of  which  is 
formed  by  a  fold  of  the  skin  of  the  abdomen. 

Differentiation.  In  physiology,  a  development  by  a  process  of  evolution;  as 
when  a  reed  develops  roots  and  stems,  it  is  called  a  development  by  differen- 
tiation. Or  applied  generally  to  the  growth  of  organic  bodies,  it  is  an  evolu- 
tion from  pre-existing  bodies,  as  from  the  stem. 

Diluvium.  Ancient  beds  of  gravel  and  boulders,  and  which  have  been  spread 
over  the  earth  by  water,  or  by  water  and  ice.  These  beds  were  formerly  re- 
garded as  having  been  formed  by  the  Noachian  deluge. 

Dip,  Angle  of  Dip.     Inclination  of  strata  towards  any  point  of  the  compass. 

Discoidal.     Like  a  disk,  applied  to  univalves.     Where  coils  lie  in  one  plane. 

Disintegration.  The  separation  of  the  component  particles  of  a  mass  through  the 
influence  of  water  and  the  atmosphere. 

Ditrematous.     Having  two  openings ;  a  mouth  and  a  vent. 

Dolomite.    A  limestone  containing  a  large  proportion  of  magnesia. 

Dorsal.    Belonging  to  the  back. 

Drift.    Transported  beds  of  gravel,  sand,  &c. 

Dunes.  Low  hills  of  blown  sand  which  skirt  the  shores  of  Holland,  France,  and 
England. 

Dykes,  or  Dikes.  Narrow  sheets  of  rock  which  fill  ancient  fissures,  and  which  run 
in  nearly  straight  lines ;  they  often  project  above  the  surface  like  walls,  and 
hence  their  name. 

Earth's  Crust.  Those  parts  of  the  earth  which  are  accessible  to  human  observa- 
tion. 

Ecpyrosis.     Destruction  by  fire. 

Echinoderms.  A  class  of  Radiates  whose  external  envelope  is  spinous  or  sub- 
spinous. 

Elvan.  A  Cornish  name  for  an  intruded  rock,  in  composition  between  a  porphyry 
and  granite. 

Embryon,  Embryo.  The  rudiments  of  an  animal  while  in  the  womb,  before  its 
membranes  are  visible,  and  from  which  we  have  the  following  terms :  Embry- 
ology, Embryogeny,  Embryography,  Embryotic. 

Enaliosauria.  Sea  lizards  or  marine  saurians,  whose  organs  of  locomotion  are 
paddles. 

Encrinites.  An  order  of  Echinoderms  which  are  supported  upon  a  jointed 
column. 


288  MANUAL   OF   GEOLOGY. 

JEituary.     Bays  at  the  mouths  of  rivers  where  the  water  is  only  brackish. 

Encrusting.     Spreading  on  surfaces  like  a  crust. 

Endogens.  Inside  growers;  a  large  and  important  class  of  plants  whose  woody 
fibres  are  disposed  in  bundles,  and  whose  stems  have  neither  bark  nor  a  proper 
central  pith.  Their  seeds  have  only  one  cotyledon,  and  their  leaves  are  pro- 
vided with  parallel  veins  or  nerves.  Examples :  Indian  corn,  the  grasses,  bam- 
boo, sugar  cane,  reeds,  «fcc. 

Eolian.  A  formation  of  recent  origin,  consisting  of  a  marine  sand  drifted  and 
arranged  by  the  wind. 

Epidermis.     Outer  skin. 

Epoch.     The  time  when  an  event  happened. 

Era.     A  period  comprehended  between  two  fixed  points. 

Escarpment.     Abrupt  slope. 

Evertile.     Capable  of  being  turned  inside  out. 

Exogens.     Vegetables  whose  trunks  or  stems  grow  by  additions  to  tne  outside. 

Extensile.     Capable  of  being  lengthened. 

Exuvise,  Exuviation.  The  cast  of  the  coat  or  crust  of  a  crustacean ;  the  laying 
aside  of  the  old  coat  or  crust. 

Faluns.  A  French  provincial  name  for  those  tertiary  beds  which  are  of  the  age 
of  the  Norfolk  crag. 

Family.     Genera  grouped  together  by  likeness. 

Fault.  The  sudden  interruption  of  the  continuity  of  strata,  accompanied  with  a 
displacement  on  one  side. 

Fauna.    The  aggregate  species  of  the  animals  which  are  peculiar  to  one  country. 

Felspar,  Felspathic.  A  simple  mineral  of  a  sparry  appearance ;  one  of  the  con- 
stituents of  granite ;  a  rock  mixed  with  felspar. 

Ferruginous.     Containing  oxide  of  iron  or  its  salts, 

Fertilizers.  In  agriculture,  substances  which  promote  the  growth  of  plants, 
directly  or  indirectly. 

Filament.     A  slender  thread ;  part  of  a  stamen. 

Fire-fangled.  A  manure  which  has  lost  a  large  part  of  its  value  by  excessive 
heat  and  fermentation. 

Flags.  Thin,  even  beds  of  rocks  which  readily  separate  along  the  plane  of  depo- 
sition. They  may  be  arenaceous,  argillaceous,  or  calcareous. 

Flora.     The  plants  peculiar  to  any  region  or  country  taken  in  the  aggregate. 

Fluccan,  Fluckkan.  The  softened  walls  of  metallic  veins,  which  have  disente- 
grated  to  a  pasty  or  powdery  mass,  with  little  coherence  remaining. 

Fluviatile,     Belonging  to  a  river. 

Fluvio  Marine.  Deposits  formed  at  the  mouth  of  rivers  by  the  joint  action  of  the 
sea  and  river. 

Foliaceous.     Leafy ;  bearing  leaves. 

Formation.  A  series  of  beds  which  belong  to  one  epoch ;  or  a  group  of  rocks 
associated  by  organic  affinities  and  by  geological  position. 

Fossil,  Fossiliferous.  The  remains  of  plants  and  animals  belonging  to  any  geo- 
logic formation  j  fossil-bearing  rocks. 

Frontal.     Placed  on  the  front. 

Fucoid.    A.  family  of  fossil  plants  resembling  sea  weeds. 

Galena.     A  mineral  compound  of  sulphur  and  lead. 

Ganglion.    A  knot ;  an  enlargement  in  a  nerve. 


GLOSSARY.  289 

Ganoine.  The  bony  tissue  immediately  beneath  the  enamel  of  the  scales  of  Ga- 
noids. 

Gasteropoda,  Gasteropoda.  A  class  of  mollusks  whose  locomotive  organ  is  attached 
to  the  belly. 

Gem.  In  mineralogy,  an  order  embracing  the  ornamental  stones,  as  diamonds, 
sapphires,  <fec. 

Genetic.     Relating  to  origin. 

Genus.     A  group  composed  of  allied  species. 

Geode.     A  spherical  cavity  lined  with  small  crystals. 

Glacier.  Vast  accumulations  of  granular  snow  or  ice,  covering  Alpine  regions, 
and  which  on  declivities  move  slowly  to  the  plains  below,  bearing  forward,  at 
the  same  time,  the  debris  of  the  rocks  of  their  mountains. 

Gneiss.  A  laminated  pyro-crystalline  rock,  often,  but  incorrectly,  stated  to  be 
stratified. 

Gossan,  Gozzan.  The  hydrous  peroxide  of  iron,  mixed  more  or  less  with  decom- 
posed rock ;  the  former  is  derived  from  the  sulphides  of  iron,  or  copper  and 
iron.  The  depth  of  the  decomposition  depends  upon  the  depth  where  water 
is  constant. 

Granite.  A  massive  pyro-crystalline  rock  composed  usually  of  quartz,  felspar, 
and  mica. 

Granulated,  Granular.     Reduced  to  grains ;  made  up  of  grains. 

Grauwacke  (nearly  obsolete).  A  German  name  for  some  of  the  members  of  tho 
Palaeozoic  rocks. 

Greenstone.     Trap,  composed  of  hornblende  and  felspar. 

Green  Manure.  Formed  of  a  growing  crop  of  clover,  rye,  peas,  or  some  other 
vegetable,  and  turned  under  by  the  plough. 

Gregarious.     Associating  together  in  numbers,  or  in  flocks. 

Green  Sand.     The  lower  cretaceous  beds  containing  particles  of  silicate  of  iron. 

Grit,  Grits.     A  sharp-grained  sandstone;  or  beds  of  angular  or  rounded  quartz. 

Gymnosperm*.     Flowering  plants  with  naked  seeds. 

Gypsum.  Plaster  of  Paris;  sulphate  of  lime;  a  mineral  composed  of  sulphuric 
acid  and  lime;  a  valuable  fertilizer,  and  accompanies  rock  salt  and  brino 
springs. 

Gyrogonites.     The  spiral  seed  vessels  of  plants  belonging  to  the  order  Characete. 

Hamilton  Group.  A  series  of  dark-colored  beds  occupying  a  middle  position  in 
the  Devonian  system. 

HO.     Chemical  symbol  for  water;  the  initials  of  hydrogen  and  oxygen. 

Homogeneous.     Of  one  substance. 

Homologue.  The  similarity  of  structure  in  organs  :  as  the  wings  of  birds  and  the 
paddles  of  the  whale.  It  is  also  applicable  to  individual  parts :  as  a  particular 
bone  in  the  hand  of  man  is  the  homologue  of  one  in  the  paddle  of  a  whale,  and 
hence,  hotnologize  is  a  process  by  which  homologies  are  determined.  In  this 
connection  we  have  homologous,  homologically,  homological. 

Homology.  Relations  which  exist  in  organs  belonging  to  one  type  of  structure, 
as  the  arm  of  a  man  and  tho  foreleg  of  a  horse. 

Homomorphous.     In  botany,  similarity  in  shape. 

Hornblende.  A  simple  mineral  of  a  dark  green  color,  and  is  also  a  member  of  tha 
laminated  pro-crystalline  rocks. 

Hydro.    As  a  prefix,  has  reference  to  water. 
25 


290  MANUAL  OP  GEOLOGY. 

Hypo.    As  a  prefix,  means  under  or  beneath,  and  scarcely  differs  from  infra. 
Hypogenous.     Originating  below. 

ffypozoic.     Below  life.    The  name  applies  to  gneiss,  mica  slate,  hornblende,  Ac. 
Hornstone.     A  massive  grayish  variety  of  quartz  which  has  the  lustre  of  horn ; 

and  is  also  tough,  breaking  usually  with  a  large  conchoidal  fracture. 
Hudson  River  Group.   The  shaly  and  slaty  varieties  of  rock,  and  some  sandstones', 

above  the  Trenton  limestone ;  and  which  are  poorly  represented  in  a  few  places 

in  the  Hudson  River  Valley.     The  designation  turns  out  an  improper  one, 

though  very  generally  used. 
Humus.     Vegetable  mould ;  a  dark  brown  vegetable  matter,  intermixed  largely 

with  new  or  uncultivated  soils. 
Iceberg.    A  mass  of  floating  ice  originating  in  the  polar  regions.     They  bear 

debris,  and  distribute  it  over  the  bottom  of  the  ocean  along  the  course  over 

which  they  float. 

Ichnology.     The  science  which  treats  of  the  footprints  of  extinct  animals. 
Igneous  Rocks.     Rocks  which  have  been  acted  upon  by  the  internal  fires  of  the 

earth,  and  which  have  been  forced  to  the  surface  in  the  condition  of  molten 

matter,  as  trap,  lava,  «fec.,  including  granite. 
Increment.     Augmentation  by  addition,  and  not  by  evolution  from  pre-existing 

parts. 

Individuals.     The  units  belonging  to  the  different  kinds  of  existences. 
Inductive  Science.    Associated  facts  strung  together,  or  so  combined,  as  to  enable 

us  to  discover  causes. 

Inorganic.    Without  organs,  and  which  are  independent  of  vital  action,  as  mine- 
rals, the  mineral  kingdom. 

In  situ.     Unmoved,  or  in  the  place  where  formed. 
Inter.    As  a  prefix  denotes  between. 
Invertebrata.     Animals  without  vertebrae. 
Isothermal.     Lines  along  which  the  temperatures  are  equal. 
Joints.    The  planes  indicated  by  lines  on  the  faces  of  many  rocks.    These  lines 

become  visible  by  the  slight  separation  of  regular-shaped  masses  from  each 

other.     They  lie  obliquely  to  the  bedding  planes. 
Kaolin.     China  clay,  or  clay  arising  from  decomposing  felspar. 
Kibble.    A  large  bucket  for  elevating  ore. 
Lacustrine.     Produced  by  or  belonging  to  lakes. 

Lamellibranchiata.    Shell  fish  provided  with  lamellar  gills ;  as  clam  and  oyster. 
Lamelliferous.     Made  up  of  thin  plates  like  paper. 
Laminse,  Lamination,  Laminated.     Thin  crystalline  plates  into  which  a  rock  may 

be  divided.     Laminae  proper  are  never  made  up  of  rounded  grains,  or  embrace 

fossils. 

Lava.     The  molten  rock  derived  from  a  volcano. 
Lias,  Liassic.    An  English  provincial  name  for  the  lower  strata  of  the  Jurassic 

system. 

Lignite.     Carbonized  wood  which  retains  its  original  structure. 
Limit  of  Activity.   The  size  or  bulk  at  which  an  organism  loses  its  power  of  loco- 
motion. 
Linear.    Like  a  line,  or  long  and  slender  tissue  or  organ  whose  sides  or  margins 

are  nearly  parallel,  as  the  leaves  of  grasses. 
Lite.    As  a  suffix  relates  to  stone,  being  derived  from  lithos,  a  stone. 


GLOSSARY.  291 

Lithological.    Used  to  express  the  mineral  character  of  a  rock  or  formation. 

Lithographic  Stone.     One  suitable  for  lithography. 

Littoral.    A  zone  between  high  and  low  water  in  zoological  geography. 

Loess.     A  name  given  to  a  post-tertiary  formation  upon  the  Rhine. 

Longitudinal.     Arranged  lengthwise. 

Loricatcd.     Reptiles  furnished  with  dermal  bony  plates. 

Lycopodites.  Fossil  plants  closely  allied  to  the  club  mosses  or  ground  pines.  The 
Lycopodiaceae  is  a  natural  family  of  flowerless  plants  ranking  with  ferns  and 
the  vascular  Cryptogamia. 

Madrepore,     A  family  of  corals  distinguished  by  superficial  star-shaped  cavities. 

Magnesian  Limestone.  Any  limestone  which  contains  a  definite  quantity  of  mag- 
nesia.  It  is  also  an  English  name  for  a  member  of  the  Permian  system.  We 
also  apply  it  to  the  calciferous  sandstone,  as  it  always  contains  magnesia.  A 
dolomite  is  a  granular  variety  of  magnesian  limestone,  differing  in  structure 
from  the  preceding.  If,  however,  any  of  these  magnesian  rocks  are  locally 
granular,  or  rather  coarsely  crystalline,  they  are  described  as  dolomitic. 

Mammalia.     The  highest  grade  of  vertebrates,  and  which  suckle  their  young. 

Mammoth.    An  extinct  species  of  the  elephant;  the  fossil  elephant  of  Russia. 

Mammillary,  Mammillated.  A  surface  formed  of  rounded  projections,  which  are 
segments  of  a  sphere. 

Marl,  Marly.  A  mixture  of  fine  and  incoherent  carbonate  of  lime  with  some  clay 
and  sand.  If  it  becomes  solid  it  is  sometimes  called  indurated  marl. 

Marsupialia.  A  class  of  mammals  provided  with  an  external  pouch  for  lodging 
thoir  young,  as  the  opossum  and  kangaroo. 

Mastodon.  An  extinct  pachyderm  closely  allied  to  the  elephant,  but  its  molars 
are  mammillated. 

Mass.     The  whole  quantity  of  matter  in  a  given  body  or  in  a  given  bulk. 

Matrix.  The  bed  which  a  mineral  or  shell  still  occupies.  The  supporting  or 
enclosing  matter. 

Mechanical  Origin.  When  the  origin  of  a  rock  is  effected  by  an  external  force, 
as  water  flowing  in  streams,  currents,  <fcc.,  it  is  used  in  contradistinction  to 
rocks  which  may  be  said  to  have  a  chemical  origin,  or  whose  particles  have 
been  consolidated  by  a  chemical  force. 

Medial.     Passing  along  the  middle. 

Mesozoic.     Middle  life. 

Metamorphic  Rocks.  Those  which  have  been  altered  since  they  were  consoli- 
dated. Rocks  undergo  a  limited  change  by  the  influence  of  heat  from  a  trap 
dyke.  There  is  no  proof  that  ordinary  gneiss,  mica  slate,  «fcc.,  are  altered 
sediments. 

Metamorphosis.  Change  of  form  by  which  a  caterpillar  or  larva  becomes  a  fly, 
a  chrysalis,  or  a  butterfly. 

Mica  Slate,  Mica  Schist.  A  rock  composed  of  quartz  and  mica  with  a  thin  lami- 
nated structure,  and  usually  fissile  through  the  mica  planes. 

Mineralogy.     The  science  which  treats  of  minerals. 

Miocene.  The  middle  division  of  the  Tertiary.  A  minority  of  its  mollusks  are 
living  in  our  seas. 

Molasse.     A  series  of  tertiary  beds  in  Switzerland. 

Mollusca,  Molluscous.  One  of  the  great  branches  of  the  animal  kingdom,  em- 
bracing those  animals  which  have  soft  bodies  like  the  clam  and  oyster. 


292  MANUAL   OF   GEOLOGY. 

Mono.     As  a  prefix,  denotes  single  or  one;  as  monodelphic,  one  brotherhood. 

Monogeneric.     Oneness  of  origin. 

Monotrematous.     Having  but  one  opening  to  the  body  which  serves  for  a  mouth 

and  vent;  or  one  orifice  for  urine  and  faeces. 
Moraine,     The  debris  of  mountains  brought  down  to  the  valleys  by  glaciers,  and 

which  is  arranged  in  ridges. 
Morpho.     As  a  prefix,  relates  to  form. 
Morphology.     The  science  which  treats  of  the  forms  of  the  organs  or  parts  of 

animals  or  plants. 

Motile.     Possessing  the  power  of  self-motion  without  will  or  consciousness. 
Mountain  Limestone.     The  lower  or  older  beds  of  the  Carboniferous  system. 
Muriate  of  Soda.     One  of  the  chemical  names  for  common  table  salt. 
MuscJielkalk.     The  middle  member  of  the  Triassic  system.     A  marine  calcareous 

deposit. 

Mycology.     The  science  which  treats  of  mushrooms. 

Nagelflue.     A  conglomerate  rock  belonging  to  the  Tertiary  of  Switzerland. 
Natatory.     Formed  for  swimming. 

Naturalism.     A  pantheistic  creed  which  claims  to  be  founded  upon  natural  phe- 
nomena, maintaining  that  all  that  exists  is  simply  a  succession  of  phenomena. 

It  is  destitute  of  religious  elements. 

Neocomian  Stage.     Lower  green-sand,  according  to  some  English  geologists. 
Neozoic.     Formations  more  recent  than  the  palaeozoic. 
Neptunian.     Aqueous  deposits. 
N6ve.     The  highest  part  of  a  glacier. 

New  Red  Sandstone.     One  of  the  common  names  for  the  Triassic  system. 
Nodule.     A  rounded  mass,  formed  by  a  molecular  force  and  destitute  reticulated 

veins  of  foreign  matter. 

Normal.     Ordinary,  or  as  a  body  usually  appears ;  according  to  law. 
Obsolete.     In  natural  history,  obscure,  indistinct. 
Old.     As  a  suffix,  indicates  similar  to,  or  like  another  object. 
Old  Red  Sandstone.     A  member  of  the  Devonian  system. 
Onondaga  Limestone.     It  takes  its  name  from  Onondaga  Co.,  N.  Y.     It  is  the 

limestone  member  of  the  Devonian  system. 
Oolite,  Oolitic.     A  limestone  made  up  of  roundish  grains  similar  to  the  roe  of  a 

fish.    It  is  also  a  rock  belonging  to  the  Jurassic  system. 

Operculum.     The  plate  or  valve-like  body  which  closes  the  mouth  of  univalves. 
OpJiidia.     An  order  of  reptiles  containing  the  serpents. 
Oral.     Belonging  to  the  mouth. 

Organic,  Organized.     Having  organs  ;  produced  by  vital  action. 
Organic  Remains,  Fossils.     Remains  of  animals  and  plants  in  sedimentary  rocks. 
Orthocerata,  Orthoceratitee.   Mollusks  belonging  to  the  class  Cephalopoda,  whose 

shells  are  straight  and  chambered. 

Osar.     Ridges  of  stone,  and  in  which  is  mixed  gravel  and  sand. 
Oscillations.     Movements  to  and  fro,  like  the  pendulum  of  a  clock. 
Osteology.     That  part  of  anatomy  which  treats  of  bones. 
Otolites.     Ear-bones  of  fishes. 
Outliers.    Isolated  strata  which  are  now  found  at  a  distance  from  the  main  body 

of  the  formation  to  which  they  belong. 
Ovate.     Egg-shaped. 


GLOSSARY.  293 

Oxide.  A  combination  of  oxygen  with  another  body,  as  iron,  forming  a  com- 
pound called  an  oxide,  as  the  oxide  of  iron  in  the  condition  of  iron  rust. 

Oxygen.  A  simple  gaseous  body  which  supports  respiration  and  combustion.  It 
is  a  constituent  part  of  the  atmosphere  and  water. 

Pachydermata.  An  order  of  animals  with  thick  skins,  as  the  elephant,  tapir,  and 
extinct  mastodon. 

Palaeozoic,  Palaeozoic  Rocks.  Ancient  life ;  a  division  of  rocks  which  terminate 
upward  with  the  Permian  system.  This  division  contains  no  species  of  ani- 
mals or  plants  which  are  now  living. 

Paleontology.     The  science  which  treats  of  fossils. 

Palates.     Crushing  teeth  of  sharks  and  rays. 

Palliobranchiata.  Mollusks  furnished  with  a  pallium  or  cloak,  and  which  per. 
forms  the  office  of  gills. 

Paragenesis.  To  be  present  with,  or  the  co-existence  and  mode  of  association  of 
mineral  bodies. 

Parasite.     Living  on  animals  as  their  home  or  residence. 

Pectinated.     Set  like  the  teeth  of  a  comb. 

Pelagian,  Pelagic.     Belonging  to  the  deep  sea. 

Petroleum.     A  liquid  mineral  pitch  and  highly  combustible. 

Phsenogamous,  Phsenogomic  Plants.  A  branch  of  the  vegetable  kingdom,  all  the 
individuals  of  which  bear  flowers  and  seed,  as  the  rose,  tulip,  Indian  corn, 
grass,  &c. 

Pinnse,  Pinnate.     Processes  set  in  rows  like  the  beards  of  a  feather. 

Pit  Coal.  So  called  originally  because  it  was  obtained  by  sinking  pits  in  the 
rock  or  ground. 

Placer.     A  name  given  to  deposits  of  gold. 

Plaginyona.     With  lateral  muscles. 

Plastic  Clay.  A  clay  of  the  lower  Eocene  period ;  so  called  from  its  moulding 
properties.  The  term  is  nearly  obsolete. 

Pleistocene.     Most  recent. 

Pliocene.  The  third  division  of  the  Tertiary  series.  The  proportion  of  living 
mollusks  is  greater  than  the  extinct. 

Plutonic,  Plutonic  Hocks.  A  name  applied  to  granite  rocks  originating  below  by 
the  agency  of  heat,  some  porphyries,  <fec.  They  are  supposed  to  have  been  per- 
fectly fused,  and  to  have  consolidated  and  crystallized  from  that  condition. 

Poicilitic.  Variously  colored,  variegated ;  a  term  applied  to  the  red,  blue,  and 
green  marls  of  the  Triassic  system. 

Poly.     As  a  prefix,  indicates  many. 

Polyzoary.     The  united  mass  of  many  Polyzoa  organically  connected. 

Porphyry,  Porphyritic.  A  submarine  pyro-plastic  rock  which  contains  crystals 
of  felspar  in  a  compact  base.  Any  rock  is  porphyritic  which  has  crystals  of 
felspar  in  a  compact  base,  or  one  which  approaches  this  condition. 

Pre.     As  a  prefix,  denotes  before;  as  pre-glacial,  before  the  glacial  period. 

Precipitate.  The  matter  separated  from  a  solution  by  a  reagent,  and  which  sub- 
sides to  the  bottom  of  the  vessel;  any  fine  matter  which  separates  and  finally 
subsides  to  the  bottom  in  the  condition  of  a  fine  powder. 

Prehensile.     Capable  of  catching  hold. 

Primordial.     Existing  from  the  first. 

Pro.    As  a  prefix,  means  before. 


294  MANUAL  OP   GEOLOGY. 

Proboscidian.    An  order  of  mammals  provided  with  a  proboscis  or  trunk,  as  the 

elephant. 

Proto.    As  a  prefix,  denotes  first ;  as  protozoa,  first  life. 
Protozoic.     First  life. 
Pseudo.   As  a  prefix,  implies  something  false ;  but  its  meaning  is  modified  by  the 

subject  to  which  it  applies. 

Ptericthys.     A  winged  fish  belonging  to  the  Devonian  period. 
Pterodactyles.     Flying  lizards. 

Puddingstone.     A  pebbly  bed  consolidated  in  the  air. 
Pumice.     A  porous  lava  which  floats  on  water. 
Purbeck  Limestone,  Purbeck  Beds.     A   fresh   water   deposit  belonging   to   the 

Wealden  of  England.     It  contains  many  small  extinct  mammalian  remains. 
Purposive.     In  doctrine,  it  implies  any  change  which  is  for  a  purpose. 
Pyrites,  Iron  Pyrites,  and  Copper  Pyrites.     Compounds  of  sulphur  and  iron,  or 
sulphur,  iron,  and  copper.     The  first  is  sometimes  called  fools'  gold.     In  North 
Carolina  it  is  generally  auriferous.     It  is  one  of  the  most  generally  diffused 
metallic  compounds  known. 
Pyrogenous.     Originating  in  fire. 

Quadrumana.     Four-handed ;  an  order  of  mammals  including  the  monkeys. 
Qua- Qua-  Versal  Dip.     Beds  which  dip  to  all  points  of  the  compass. 
Quartz,  Limpid  Quartz,  Quartz  Crystals.     It  is  a  pure  form  of  silex,  or  nearly  so. 
Quartzite.     A  rock  consisting  mostly  of  amorphous  quartz,  sometimes  in  the  form 

of  chert  or  hornstone. 
face.     The  descendants  of  a  stock.     It  may  be  used  generally,  as  the  race  of 

Adam,  or  restricted,  as  the  race  of  Abraham. 
Hacking.     In  mining,  the  separation  of  broken  rock  from  earth  by  shaking  in  a 

frame. 
Bake  Vein.    A  sheet  of  mineral  matter  or  vein  standing  nearly  vertically,  and 

quite  uniform  in  thickness. 

Ratio.     The  relation  which  one  quantity  bears  to  another. 
Be.    As  a  prefix,  means  repetition. 
Beptatory.     Creeping  ;  creeping  animals. 

BMzopod.     Feet  extending  out  like  roots  and  thrust  out  at  will.    A  microscopic 
animal  of  the  lowest  grade.     Most  species  occupy  multicellular  shells, -and  are 
called  Palythalamia. 
Bodentia,  Rodents.    An  order  of  animals  provided  with  two  cutting  teeth  in  each 

jaw,  shaped  like  a  chisel. 
Roth-todt-liegendes.    The  oldest  rock  of  the  Permian  system,  and  so  called  by  the 

German  miners.     It  is  a  red  sandstone  beneath  the  Keuper  Schiffer. 
Row  Culture.     In  agriculture,  cultivation  of  crops  in  drills  or  rows. 
Rubble.     A  fragmentary  rock,  slightly  decomposed,  which  overlies  certain  quar- 
ries of  rock,  so  called  by  quarry  men. 
Ruminantia.     An  order  of  animals  which  chew  their  cud  or  ruminate,  as  the  ox, 

deer,  Ac. 

Saccharoidal.     White  and  granular  like  loaf  sugar. 
Saccharine.     The  sweet  taste  of  sugar. 

Salses.    Eruptions  of  mud  or  of  vapor  accompanied  with  the  escape  of  heat. 
Saltatorial.     Moving  by  leaps. 


GLOSSARY.  295 

Sarcode.  A  peculiar  form  of  soft,  fleshy,  extensile  matter  of  the  rhizopod,  no 
distinct  tissue. 

Sauria,  Saurians.  An  order  of  reptiles  containing  both  the  scaly  and  loricated 
families.  Alligators. 

Scar.    A  bold  precipice  of  rock  nearly  equivalent  to  the  term  bluff. 

Schist.     It  is  often  used  as  a  synonym  for  slate ;  slaty. 

Seams.  Thin  layers,  or  sheets  of  mineral  differing  in  kind  from  the  enclosing 
rock. 

Secondary,  Secondary  Rocks.  The  name  is  now  applied  to  the  same  division  of 
rocks  as  the  Mesozoic. 

Section.    A  face  of  rocks  exposed  by  nature  or  art,  represented  in  a  drawing. 

Sediments,  Sedimentary  Hocks.  All  materials  which  have  been  deposited  under 
water,  or  by  its  instrumentality. 

Septse,  Septum.     A  partition  between  cavities. 

Septaria.  Roundish  masses  of  limestone  checkered  internally  and  sometimes 
externally,  and  traversed  by  seams  of  spar  dividing  the  mass  into  angular 
parts.  They  are  formed  in  rocks,  while  the  materials  are  still  in  a  plastic 
state,  by  molecular  attraction.  These  masses  undergo,  during  farther  consoli- 
dation, a  shrinkage  which  forms  cracks,  and  which  are  subsequently  filled  by 
calcspar  or  barytes,  &c. 

Sessile.     Without  footstalks. 

Shale.     A  consolidated  clay  less  firm  than  slate;  it  is  sometimes  bituminous. 

Shell  Marl.     A  deposit  of  clay  containing  lime  and  shells. 

Shingle.     The  sands  and  gravel  of  a  sea  beach. 

Shoding.     To  trace  out  veins  by  fragments  of  ore  upon  the  surface. 

Silex,  Silica,  Silicious.  A  combination  of  silicon  and  oxygen;  it  is  the  pure 
earth  or  pure  quartz,  and  is  the  most  common  mineral  substance  in  nature.  It 
resists  for  a  long  time  the  action  of  atmospheric  agents.  It  forms  the  frame- 
work of  the  globe. 

Silt.  The  finest  sand  transported  by  water,  and  which  accumulates  at  the  mouths 
of  rivers. 

Silurian.  A  name  given  by  Sir  Roderick  I.  Murchison  to  a  system  of  palaeozoic 
rocks  well  developed  in  ancient  Siluria,  a  kingdom  once  inhabited  by  the 
Silures  on  the  border  of  Wales. 

Simple.  In  chemistry,  an  undecomposed  body.  In  mineralogy,  one  that  is  ho- 
mogeneous. 

Sinistral.     In  shells,  turning  from  east  to  north. 

Sinter.     A  deposit  from  mineral  springs;  it  may  be  calcareous  or  silicious. 

Snow  Line.     The  line  of  perpetual  frost  or  snow,  15,000  feet  at  the  equator. 

Species.  The  collective  individuals  which  are  alike  in  all  their  essential  cha- 
racters. 

Spermatozoa,  Spermatozoum.  Singular  motile  cells  in  the  seminal  fluid  which 
impregnates  the  ovum. 

Spherules.     Bodies  of  a  globular  form. 

Spores.     The  productive  germs  of  cryptogamic  plants. 

Stalactite.  Dependent  cylindrical  shafts  attached  to  the  roofs  of  limestone  caves 
like  an  icicle,  and  produced  by  the  filtration  of  water  through  the  rock  dissolv- 
ing the  carbonate  of  lime  in  its  progress;  a  portion  of  the  water  drops  from 


296  MANUAL   OF   GEOLOGY. 

the  point,  and  deposits  the  remainder  of  the  carbonate  on  the  floor,  and  there 

forms  a  mass  which  is  called  stalagmite. 
Station.     The  situation  in  which  a  species  naturally  occurs. 
Sloping.     Mining  by  removing  in  layers  from  above  downwards. 
Strata,  Stratum.     Layers  of  rock  which  are  parallel  or  nearly  so,  and  which  are 

deposited  from  water.     They  lie  like  the  leaves  of  a  book. 
Stratified.     Debris  arranged  in  strata  by  water. 
Strike.     Direction  of  the  outcrop  of  strata.     It  is  always  at  right  angles  to  the 

dip.     It  is  also  called  the  line  of  bearing. 
Styles.     Stiff  unjointed  processes  tapering  to  a  point. 
Sub.    As  a  prefix,  implies  under,  or  used  to  express  diminutions  of  a  quality  near 

to  ;  as  sub-equal,  nearly  equal. 

Super.     As  a  prefix,  implies  above,  or  in  certain  cases  excess. 
Suture.    A  mark  or  seam  where  two  edges  meet. 
Syenite.     A  kind  of  granite  in  which  hornblende  takes  the  place  of  mica.     The 

name  is  derived  from  Syene  in  Egypt. 
Synclinal  Axis.     Formed  by  the  dipping  of  strata  towards  each  other  or  inwards. 

It  is  the  opposite  of  Anticlinal  axis. 
System.   A  group  of  rocks  having  such  relations  as  to  admit  or  require  their  union 

in  a  systematic  classification. 

Talus.     The  fragments  of  rocks  or  debris  at  the  base  of  a  cliff;  they  form  a  slop- 
ing declivity  of  loose  materials. 

Taxonomy.     In  natural  history,  laws  and  principles  of  classification. 
Teleology.     The  science  of  ends  in  nature  and  art,  or  of  final  causes. 
Tentacles.     Slender,  contractile,  unjointed  organs  of  polypes. 
Terrain.     The  French  word  for  formation. 
Tertiary.     The  youngest  great  division  of  sediments. 
Testacea.     Animals  which  are  covered  with  a  shell  or  test. 
Testudinata.     An  order  of  reptiles  familiarly  known  as  the  turtles. 
Thin  out.     The  diminution  in  thickness  in  rocks  in  any  given  direction,  or  which 

may  become  wedgeform. 

Tissues.     The  soft  substances  which  make  up  a  living  body. 
Till.     Beds  of  clay  with  intermixed  boulders. 
Trap.   Igneous  rocks  which  have  been  projected  through  fissures  or  rents  in  older 

rocks.     Derived  from  trappa,  a  stair. 

Travertin.     A  deposit  of  porous  carbonate  of  lime,from  springs. 
Trenton  Limestone.     A  Lower  Silurian  limestone. 
Tri.     As  a  prefix,  implies  thrice. 

Trilobite.     An  extinct  crustacean,  generally  divided  into  three  lobes. 
Truncate.     Ending  abruptly,  as  if  cut  off. 
Tuff,  Tufa.     Volcanic  scoria. 
Tunicata,  Tunicates.     A  class  of  mollusks  covered  with  a  leathery  sac  instead  of 

a  shell. 
Type.     The  things  and  beings  which  combine  in  themselves  the  most  important 

characteristics  of  the  group  to  which  they  belong. 
Umbilicus.     The  hollow  axis  of  some  gasteropods  around  which  the  spire  is  built 

up. 

Un.     As  a  prefix,  has  a  negative  meaning. 
Unconformable.     Strata  which  have  diverse  dips. 


GLOSSARY.  297 

Under  Clays.    A  term  applied  to  clays  beneath  a  coal  seam. 

Uni.     As  a  prefix,  implies  one ;  as  unilateral,  one  sided. 

Veins.  Sheets  of  ore  or  of  minerals  unconformable  to  the  beds  or  lamina  of  the 
rock  enclosing  them. 

Vitrification.     The  conversion  of  a  body  into  a  mass  resembling  glass. 

Vvgg.     A  cavity  in  a  lode. 

Waterdoy.     The  common  name  of  the  proteus. 

Zoid.  A  cell  having  motion  ;  as  the  spermatozoa  :  or  it  is  applied  to  an  animal 
in  an  inferior  stage  of  development ;  or  a  single  animal  in  a  group  of  zoo- 
phytes. 

Zoophytes.  A  class  belonging  to  the  radiates,  commonly  known  as  the  corals : 
by  some  authors  it  embraces  the  sponges. 


TJSIVBESITT 


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